Grammar rules

Subject-verb agreement

The subject and verb must match in number. Example: The dog runs. What not to do: The dog run.

Sentence boundaries

A complete sentence must have a subject and verb and express a full thought. Example: I studied hard, and I passed the test. What not to do: I studied hard and passed the test.

Run-on sentence

Two complete sentences are joined incorrectly without proper punctuation or a connector. Example: I studied hard; I passed the test. What not to do: I studied hard I passed the test.

Comma splice

Two complete sentences are joined with only a comma. Example: I studied hard, so I passed the test. What not to do: I studied hard, I passed the test.

Fragment

An incomplete sentence that does not express a full idea. Example: Because I was tired, I went to bed early. What not to do: Because I was tired.

Modifiers

A modifier is a word, phrase, or clause that describes another part of the sentence. It must be placed close to what it describes so the meaning is clear. Example: Running quickly, the athlete crossed the finish line. What not to do: Running quickly, the finish line was crossed by the athlete.

Dangling modifier

A modifier that does not clearly describe the correct word in the sentence. Example: After studying all night, Maya aced the test. What not to do: After studying all night, the test was easy.

Misplaced modifier

A modifier that is placed too far from the word it describes, making the sentence confusing. Example: She only ate cookies yesterday. What not to do: She ate only cookies yesterday if you mean she ate nothing else all day.

Pronouns

A pronoun must clearly refer to a noun and agree in number. Example: Each student must bring his or her notebook. What not to do: Each student must bring their notebook.

Verb tense

Verb tense should stay consistent unless the time changes. Example: Yesterday I walked to school and finished my homework. What not to do: Yesterday I walk to school and finished my homework.

Parallel structure

Items in a list or comparison should have the same grammatical form. Example: She likes reading, swimming, and biking. What not to do: She likes reading, swimming, and to bike.

Comparisons

Compare like things and make sure the sentence is logically clear. Example: My car is faster than my brother’s car. What not to do: My car is faster than my brother.

Apostrophes

Apostrophes show possession or form contractions. Example: don’t, the student’s book. What not to do: the students book if you mean one student’s book.

Singular possessive apostrophe

Use apostrophe + s for one owner. Example: the teacher’s desk. What not to do: the teachers desk.

Plural possessive apostrophe

For most plural nouns ending in s, add the apostrophe after the s. Example: the teachers’ desks. What not to do: the teacher’s desks if you mean more than one teacher owns the desks.

Comma

Use a comma after an introductory phrase, before a coordinating conjunction joining two complete sentences, and in lists. Example: After lunch, we went outside. What not to do: After lunch we went outside if the intro needs separation.

Semicolon

Use a semicolon to join two closely related complete sentences. Example: I was tired; I went to bed early. What not to do: I was tired; and I went to bed early.

Colon

Use a colon after a complete sentence to introduce a list, explanation, or example. Example: Bring three items: water, snacks, and a jacket. What not to do: Bring: water, snacks, and a jacket.

Dash

Use a dash to add emphasis or extra information. Example: My sister — who lives in Texas — is visiting. What not to do: My sister, who lives in Texas, is visiting if the dash is not needed.

Parentheses

Use parentheses for extra information that is not essential to the sentence. Example: My aunt (who is a doctor) called. What not to do: My aunt who is a doctor called if the extra info is essential.

Contrast transition

Shows difference or opposition between ideas. Examples: however, but, yet, nevertheless, on the other hand. Example: I wanted to go; however, it started raining.

Additive transition

Adds more information to an idea. Examples: also, moreover, furthermore, in addition. Example: The team practiced; moreover, they studied film.

Cause/effect transition

Shows a reason or result. Examples: therefore, consequently, as a result, thus. Example: It snowed overnight; therefore, school was delayed.

Example transition

Introduces an example or illustration. Examples: for example, for instance, specifically. Example: Many animals hibernate; for example, bears sleep through winter.

Sequence transition

Shows order or steps. Examples: first, next, then, finally. Example: First, mix the ingredients; then, bake the cake.

Conclusion transition

Signals a summary or final thought. Examples: in conclusion, overall, therefore, thus. Example: In conclusion, the plan worked well.