ACT Grammar High-Frequency Test Points | ACT语法高频考点解析

📚 ACT Grammar High-Frequency Test Points | ACT语法高频考点解析

The ACT English section tests grammar in context through five passages and 75 multiple-choice questions. About 40–45 questions cover usage and mechanics (punctuation, grammar, sentence structure), while the rest target rhetorical skills such as organization and style. This article breaks down the highest-frequency grammar rules you must master to boost your score quickly.

ACT英语部分通过五篇文章、75道选择题来考查语法在语境中的运用。其中约40至45题涉及用法与机制（标点、语法、句子结构），其余题目考查修辞技巧，如组织与风格。本文梳理了你必须掌握的高频语法规则，帮助你快速提分。

1. Commas | 逗号

Commas are the most tested punctuation mark on the ACT. You need to master four core uses: separating items in a list, joining two independent clauses with a coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, so), setting off non-essential phrases, and separating introductory elements. The ACT accepts the Oxford comma, so red, white, and blue is always correct.

逗号是ACT考试中最常考的标点符号。你需要掌握四种核心用法：分隔并列项、用并列连词（FANBOYS：for, and, nor, but, or, yet, so）连接两个独立分句、隔开非必要成分、以及分隔句首修饰语。ACT接受牛津逗号，因此red, white, and blue总是正确的。

When a comma is used with a FANBOYS conjunction, both sides must be complete clauses. If the second part is not a clause, the comma is wrong. For example, She studied hard, and passed the test is incorrect because passed the test has no subject; the correct form is She studied hard and passed the test.

当逗号与FANBOYS连词连用时，两侧都必须是完整的独立分句。如果后半部分不是分句，逗号就是多余的。例如，She studied hard, and passed the test是错误的，因为passed the test缺少主语；正确形式是She studied hard and passed the test。

Another frequent trap: do not place a comma between a subject and its verb. A sentence like The student who studied all night, scored well incorrectly separates the subject the student from the verb scored. Use paired commas only around the non-essential clause: The student, who studied all night, scored well.

另一个常见陷阱：不要在主语和谓语之间加逗号。例如The student who studied all night, scored well错误地把主语the student和谓语scored分开了。只有在非必要从句两侧使用成对逗号：The student, who studied all night, scored well。

2. Semicolons | 分号

A semicolon connects two closely related independent clauses without a conjunction: The test was difficult; I finished just in time. This is a favorite ACT pattern because answer choices often replace a correct semicolon with a comma splice or a period. The key rule: whatever appears on either side of a semicolon must be a complete sentence.

分号无需连词即可连接两个紧密相关的独立分句：The test was difficult; I finished just in time.这是ACT最爱的考点之一，因为选项常常用逗号拼接或句号来替换正确的分号。关键规则：分号两侧都必须是完整的句子。

Semicolons also appear before conjunctive adverbs such as however, therefore, moreover, nevertheless, and consequently. The pattern is complete clause; however, complete clause. A common wrong answer places a comma before however, creating a comma splice. Example: I wanted to attend; however, I had a prior engagement — correct.

分号还可用于however, therefore, moreover, nevertheless, consequently等连接副词之前。结构是完整分句; however, 完整分句。常见错误选项是在however前加逗号，造成逗号拼接。例如：I wanted to attend; however, I had a prior engagement——这是正确的。

Remember: never use a semicolon with a FANBOYS conjunction. I studied hard; and I passed is wrong; use either the semicolon alone or the comma with and.

切记：分号不能和FANBOYS连词同时使用。I studied hard; and I passed是错误的；要么只用分号，要么用逗号加and。

3. Colons and Dashes | 冒号与破折号

A colon must be preceded by a complete sentence and functions to introduce a list, an explanation, or a quotation. The ACT frequently tests whether the material before the colon is an independent clause. For instance, My backpack contains: a laptop, a notebook, and a calculator is wrong because my backpack contains is not a complete sentence. The correct form: My backpack contains a laptop, a notebook, and a calculator, or My backpack contains three items: a laptop, a notebook, and a calculator.

冒号前必须是完整的句子，用于引出一系列列举、解释或引文。ACT经常考查冒号前是否为独立分句。例如，My backpack contains: a laptop, a notebook, and a calculator是错误的，因为my backpack contains不是完整句子。正确形式是：My backpack contains a laptop, a notebook, and a calculator，或My backpack contains three items: a laptop, a notebook, and a calculator。

Dashes set off non-essential information or signal an abrupt break in thought. ACT generally accepts the em dash (—) in the standard “NO CHANGE” position. A single dash is rarely correct; dashes usually come in pairs: The candidate — a seasoned diplomat — answered every question. Do not mix dashes with commas in the same pair: The candidate, a seasoned diplomat — answered is wrong.

破折号用来隔开非必要信息或表示思路的突然转折。ACT通常接受“NO CHANGE”位置上的长破折号（—）。单独的破折号很少正确；破折号通常是成对出现的：The candidate — a seasoned diplomat — answered every question.不要在同一组内混用逗号和破折号：The candidate, a seasoned diplomat — answered是错误的。

4. Apostrophes | 撇号

Apostrophes serve two purposes on the ACT: contractions and possession. The most commonly tested trap is its vs. it’s. It’s only means it is or it has; the possessive form is its: The company increased its revenue. Since ACT passages rarely require contractions in formal context, it’s is usually wrong unless the verb is is clearly needed.

撇号在ACT中有两种用途：缩写和所有格。最常见的陷阱是its与it’s的辨析。It’s只表示it is或it has；所有格形式是its：The company increased its revenue。由于ACT文章在正式语境中很少需要缩写，除非明确需要动词is，否则it’s通常为错误选项。

For singular possessive, add ‘s: the student’s book. For plural nouns ending in s, add only an apostrophe: the students’ books. For irregular plurals, add ‘s: the children’s toys. ACT also tests joint possession: Tom and Jerry’s car (one car owned together) versus Tom’s and Jerry’s cars (separate cars).

单数所有格加’s：the student’s book。以s结尾的复数名词只加撇号：the students’ books。不规则复数加’s：the children’s toys。ACT还考查共同所有：Tom and Jerry’s car（共有一辆车）与Tom’s and Jerry’s cars（各自的车）之间的区别。

5. Subject–Verb Agreement | 主谓一致

Subject–verb agreement is a guaranteed topic on every ACT English test. The main challenge is that intervening phrases hide the true subject. In The box of chocolates is on the table, the subject is box, not chocolates, so the verb is singular. Cross out any prepositional phrases (of, in, with, along with, as well as) between subject and verb to find the real subject.

主谓一致是ACT英语考试每次必考的考点。最大的难点在于插入语掩盖了真正的主语。在The box of chocolates is on the table中，主语是box，而不是chocolates，因此动词用单数。遇到主语和动词之间的介词短语（of, in, with, along with, as well as）时，先划掉它们，再找真正的主语。

Indefinite pronouns also appear frequently. Singular indefinite pronouns include each, everyone, anybody, nobody, someone, either, neither — each takes a singular verb: Each of the students is ready. The pronouns both, few, many, several are plural. Watch for the tricky rule that either…or and neither…nor agree with the closer subject: Neither the teacher nor the students are coming.

不定代词也是高频考点。单数不定代词包括each, everyone, anybody, nobody, someone, either, neither——它们都搭配单数动词：Each of the students is ready。Both, few, many, several是复数。注意either…or和neither…nor遵循就近原则：Neither the teacher nor the students are coming。

Collective nouns (team, committee, audience, family) are singular when acting as one unit: The team is winning. When the sentence emphasizes individual members, the plural is possible, but the ACT usually prefers singular. Keep the verb consistent throughout the sentence — switching between singular and plural is always wrong.

集合名词（team, committee, audience, family）作为一个整体时用单数：The team is winning。当句子强调个体成员时才用复数，但ACT通常更倾向单数。全句动词必须保持一致——在单复数之间切换一定是错误选项。

6. Pronoun Agreement and Case | 代词一致与格

The ACT tests both pronoun–antecedent agreement and pronoun case. A pronoun must agree in number and gender with its antecedent. The classic trap is everyone returned their books — because everyone is singular, the correct form is everyone returned his or her books or, in modern usage, his or her. The ACT also avoids sweeping from singular to plural without cause.

ACT考查代词与其先行词在数与人称上的一致，也考查代词的格。代词必须在数和性上与先行词保持一致。经典陷阱是everyone returned their books——因为everyone是单数，正确形式是everyone returned his or her books。ACT同样避免无理由地从单数跳到复数。

Pronoun case distinguishes subject (I, he, she, we, they) from object (me, him, her, us, them). The trick is to isolate the pronoun: Between you and me is correct because me is the object of the preposition. For who vs. whom, use who as subject and whom as object; replace who with he and whom with him to test: Who called? → He called; To whom did you speak? → You spoke to him.

代词的格分为主格（I, he, she, we, they）和宾格（me, him, her, us, them）。诀窍是单独看代词：Between you and me是正确的，因为me是介词宾语。对于who和whom，who作主语，whom作宾语；用he替换who、用him替换whom来检验：Who called? → He called；To whom did you speak? → You spoke to him。

Case	Subject	Object	Possessive
Singular	I, he, she, it	me, him, her, it	my, his, her, its
Plural	we, they	us, them	our, their

7. Verb Tense and Form | 动词时态与形态

Verb tense questions on the ACT rarely test complex tense theory; they focus on consistency. If a passage is written in past tense, the verbs must stay in past tense unless a shift is logically required. A common error is an unnecessary shift: She walked into the room and sees the mess — mixed past and present; the correct form is walked…saw or walks…sees.

ACT中的动词时态题很少考查复杂的时态理论，而是聚焦一致性。如果文章用过去时叙述，除非逻辑上需要转换，否则动词必须保持过去时。常见错误是不必要的时态切换：She walked into the room and sees the mess——混用过去时和现在时；正确形式是walked…saw或walks…sees。

Also know the verb forms required after auxiliary verbs and in perfect tenses. Use the past participle after have, has, had, and select the correct irregular forms: have gone (not have went), had seen (not had saw). The ACT also tests lie vs. lay occasionally: lie (to recline) takes no object, while lay (to put down) takes an object.

还要掌握助动词后和完成时中动词的形式。在have, has, had之后用过去分词，并正确选择不规则形式：have gone（不是have went），had seen（不是had saw）。ACT偶尔考查lie与lay的区别：lie（躺下）不带宾语，lay（放下）带宾语。

8. Parallelism | 平行结构

Parallelism is one of the most frequently tested and easiest grammar points to fix. Items in a list or pair must be in the same grammatical form. The pattern: She likes running, swimming, and hiking — all gerunds. A wrong answer might shift to to hike or hikes. Check every list: if the first two items are nouns, the third must be a noun; if they are verbs, all must be verbs.

平行结构是最高频、也最容易修正的语法点之一。列表或并列中的各项必须采用相同的语法形式。例如：She likes running, swimming, and hiking——全部是动名词。错误选项可能会换成to hike或hikes。检查每一个并列列表：如果前两项是名词，第三项也必须是名词；如果是动词，就全部用动词。

Paired conjunctions require special attention: both…and, either…or, neither…nor, not only…but also. The words following each conjunction must match: The course teaches not only grammar but also writing — correct. A wrong version would be not only grammar but also how to write, which breaks the parallel structure.

成对连词需要特别注意：both…and, either…or, neither…nor, not only…but also。每个连词后面的成分必须对称：The course teaches not only grammar but also writing——正确。错误版本如not only grammar but also how to write，破坏了平行结构。

9. Modifiers | 修饰语

Modifier errors involve dangling or misplaced descriptive words and phrases. A dangling modifier occurs when the implied subject of the modifier does not match the sentence subject. Example: Walking down the street, the trees were beautiful — wrong, because the trees cannot walk. Correct: Walking down the street, I saw beautiful trees. The ACT loves this error; always ask: who is performing the action in the introductory phrase?

修饰语错误涉及悬垂或错位的描述性词语和短语。悬垂修饰语指修饰语的隐含主语与句子主语不一致。例如：Walking down the street, the trees were beautiful——错误，因为树不会走路。正确：Walking down the street, I saw beautiful trees。ACT特别喜欢这类错误；遇到句首修饰语时，永远要问：谁在实施这个动作？

Misplaced modifiers place a modifier too far from the word it describes. The man parked his car in the garage that was rusty — implies the garage was rusty, producing comedy. If the man is rusty, say The rusty man parked his car in the garage. One-word modifiers like only, almost, just, nearly must be placed next to the word they limit: She almost completed the exam (she did not finish) vs. She completed almost the entire exam (she finished most of it).

错位修饰语把修饰语放得离被修饰词太远。The man parked his car in the garage that was rusty——暗示车库锈迹斑斑，产生了喜剧效果。如果锈的是人，应写成The rusty man parked his car in the garage。Only, almost, just, nearly等单词修饰语必须紧邻所限定的词：She almost completed the exam（她没完成）与She completed almost the entire exam（她完成了大部分）含义完全不同。

10. Sentence Boundaries | 句子边界

Sentence boundary questions ask you to identify fragments, comma splices, and run-on sentences. A fragment is an incomplete sentence missing a subject or verb, or beginning with a subordinating word like although, because, while, since. Because the test was hard. is a fragment; it must attach to a complete clause: Because the test was hard, I studied longer.

句子边界题要求你识别残缺句、逗号拼接和流水句。残缺句是缺少主语或谓语、或以although, because, while, since等从属连词开头的句子。Because the test was hard.是残缺句，必须附着在完整分句上：Because the test was hard, I studied longer。

A comma splice joins two independent clauses with only a comma: I studied hard, I passed. Run-ons join them with no punctuation: I studied hard I passed. Both are always wrong. To fix a comma splice, use a period, a semicolon, or a comma plus a FANBOYS conjunction: I studied hard; I passed or I studied hard, and I passed. When the ACT offers these three correct alternatives, look for the shortest clear option, often the semicolon.

逗号拼接是只用逗号连接两个独立分句：I studied hard, I passed。流水句则完全不加标点：I studied hard I passed。两者永远是错的。修正逗号拼接可用句号、分号，或逗号加FANBOYS连词：I studied hard; I passed或I studied hard, and I passed。当ACT给出这三个正确选项时，选择最简洁清晰的版本，通常是分号。

11. Conciseness and Word Choice | 简洁与用词

The ACT favors concise expression. Redundancy questions give you a phrase that repeats meaning: the reason is because, advance forward, return back, surround on all sides. In each case, delete the redundant word: the reason is that, advance, return, surround. If an answer choice is wordier than the original and adds no new meaning, it is wrong.

ACT偏爱简洁表达。冗余类题目会给出重复含义的短语：the reason is because、advance forward、return back、surround on all sides。这些情况都应删除多余词语：the reason is that、advance、return、surround。如果某个选项比原句更冗长且没有增加新信息，那它就是错误项。

Word choice questions test commonly confused words. Master these high-frequency pairs: affect (verb: to influence) vs. effect (noun: result); then (time) vs. than (comparison); its (possessive) vs. it’s (it is); their, there, they’re; accept (to receive) vs. except (excluding); between (two items) vs. among (three or more). In context questions, read the full sentence and ask whether the word fits the intended meaning.

用词选择考查易混淆词。掌握以下高频配对：affect（动词，影响）与effect（名词，结果）；then（时间）与than（比较）；its（所有格）与it’s（it is）；their, there, they’re；accept（接受）与except（除…之外）；between（两者之间）与among（三者或以上）。遇到语境题时，通读整个句子，判断哪个词符合原意。

12. Transitions and Organization | 过渡与组织

The final category covers rhetorical organization: adding or deleting sentences, arranging sentences within a paragraph, and choosing logical transition words. The number one rule is to choose the transition that matches the relationship. However signals contrast; therefore signals cause and result; additionally signals addition; for example signals illustration. Test each option by rewriting the relationship in your own words.

最后一类考查修辞组织：添加或删除句子、在段落内排列句子、选择逻辑过渡词。首要规则是选择与逻辑关系匹配的过渡词。However表示转折；therefore表示因果；additionally表示递进；for example表示举例。判断方法：用自己的话复述前后两句的关系。

For sentence placement questions, pay attention to pronouns and repetition. A sentence containing these methods must appear after the methods are named. A sentence with a new topic belongs at the start of a paragraph; a sentence that summarizes belongs at the end. When asked to delete a sentence, check whether the surrounding sentences still flow logically — if the deleted material is never referenced again, deletion is usually correct.

对于句子位置题，注意代词和重复信息。含有these methods的句子必须出现在这些方法被提及之后。引入新话题的句子应放在段首；总结性句子应放在段末。当题目要求删除某句话时，检查周围句子是否仍然逻辑通顺——如果被删内容在文中不再被引用，删除通常是正确的。

The best way to apply these rules is to practice with real ACT English sections and track which rule you miss most often. Then revisit that specific category before every practice test. Grammar on the ACT is predictable; once you master these high-frequency patterns, your score

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ACT Grammar High-Frequency Test Points | ACT语法高频考点解析