Written Comprehension and Grammar
What the domain tests
Written Comprehension and Grammar measures two linked skills: reading a short passage for main idea, details, inference, tone, and vocabulary in context; and applying standard English grammar, punctuation, and usage. The passages are usually public-safety or general workplace topics, and the grammar items are single sentences with one clear error or one correct choice.
Core rules
- Main idea: ask what the passage is mostly about. A choice that is true but covers only one sentence is a detail, not the main idea.
- Inference: the answer must follow from the text, not from personal experience.
- Vocabulary: substitute each option into the original sentence; the correct one preserves the meaning and grammar.
- Subject-verb agreement: find the subject and ignore interrupters such as 'along with', 'as well as', and 'together with'. 'The officer, along with two witnesses, was at the scene.'
- Pronouns: match singular/plural; use 'who' for a subject and 'whom' for an object or after a preposition.
- Punctuation: singular possessive = apostrophe + s; plural possessive = s + apostrophe; plural = no apostrophe. A semicolon joins two independent clauses; a comma alone creates a comma splice.
- Modifiers: place a descriptive phrase next to the word it describes.
Worked example
Passage: 'The auxiliary officer arrived at the community center at 18:00. She checked the doors, found a broken window latch, and notified the shift supervisor. Because the building was due to close at 19:00, she stayed until maintenance secured the latch.' Question: What is the main idea? A. The center closed at 19:00. B. The officer found a security defect, reported it, and remained until it was fixed. C. Maintenance workers repaired a latch. Answer: B. A and C are true details, but B covers the officer's full sequence of actions. For a grammar item, 'The officer, along with two volunteers, ___ the room' takes 'was' because the subject is singular 'officer'; 'along with two volunteers' is parenthetical.
Traps that cost marks
- Choosing a true detail instead of the main idea.
- Over-inferring: adding motives or facts the passage never states.
- Missing subject-verb agreement when a phrase sits between subject and verb.
- Confusing 'its' (possessive) with 'it's' (it is), or putting an apostrophe in a simple plural.
- Joining two complete sentences with only a comma.
- Placing a modifier so it describes the wrong noun.