| Independent clause | A clause containing a subject and finite verb that can function as a complete sentence. | “The rain stopped” can stand alone; it can be joined to “the team returned” with a semicolon. |
| Dependent clause | A clause that requires a main clause because a subordinating word or construction makes it incomplete by itself. | “Although the rain stopped” needs a main statement: “Although the rain stopped, the field remained wet.” |
| Comma splice | Joining independent clauses with only a comma, without an appropriate joining construction. | “The rain stopped, the team returned” becomes “The rain stopped; the team returned.” |
| Subject–verb agreement | Matching a verb’s grammatical number to its subject. | “The collection of maps is upstairs”: collection is singular even though maps is plural. |
| Pronoun antecedent | The noun or noun phrase a pronoun refers to. | “After Ava met Noor, she called” leaves she ambiguous; name the intended caller. |
| Pronoun case | The form of a pronoun appropriate to its grammatical role. | “The guide spoke to Lena and me”: me is an object of to; removing Lena makes the role clearer. |
| Dangling modifier | A modifying phrase whose intended subject is absent or grammatically mismatched. | “Carrying the samples, the door opened” wrongly attaches carrying to door; write “Carrying the samples, Mira opened the door.” |
| Restrictive modifier | Information needed to identify which noun or group is meant. | “The books that have torn covers need repair” selects the torn-cover books rather than every book. |
| Nonrestrictive modifier | Additional information about an already identified noun, normally separated by paired commas. | “The atlas, which has a torn cover, needs repair” adds a detail about the identified atlas. |
| Parallelism | Using corresponding grammatical forms for equivalent coordinated elements. | “The club values planning, testing and revising” matches three gerunds; “planning, to test and revision” does not. |
| Semicolon | A mark that can join related independent clauses without a coordinating conjunction. | “The trial improved detection; errors remained.” Both sides are complete statements. |
| Colon | A mark generally following a complete clause to introduce an explanation, example or list. | “We need three supplies: gloves, labels and boxes” has a complete introducing clause. |
| Concession transition | A connective that acknowledges a contrast without simply erasing the preceding statement. | “The method is slow; nevertheless, it is reliable” retains both the limitation and benefit. |
| Comparison baseline | The reference quantity or object relative to which a comparison is made. | “Eight minutes longer than the proposal” compares two proposed routes, not either route with the old road. |
| Redundancy | Repetition that adds no needed meaning in its context. | “Both panels have the same equal area” can become “Both panels have equal areas.” |