In one line
Punctuation marks (full stop, comma, semicolon, colon, apostrophe and others) show the structure of a sentence, and misusing them changes or confuses meaning.
Explained simply
'Let's eat, Grandpa!' versus 'Let's eat Grandpa!' One comma saves Grandpa. Punctuation is the traffic signal of writing: it tells the reader where to stop, pause and turn.
Technically, punctuation organises sentences into units of meaning. Error-spotting at the TOEFL/IELTS level commonly tests apostrophes, comma splices, semicolons, colons and capitalisation.
How it works
- Apostrophe: possession (the student's book; the students' books) and contraction (it's = it is). 'Its' (possessive) has no apostrophe: 'The machine lost its power.'
- Comma splice: two complete sentences cannot be joined by a comma alone. Wrong: 'The test failed, we repeated it.' Fix with a full stop, a semicolon, or a conjunction: 'The test failed, so we repeated it.'
- Semicolon (;): joins two closely related complete sentences, or separates list items that already contain commas.
- Colon (:): introduces a list, explanation or quotation after a complete sentence: 'We need three things: time, money and skill.'
- Comma: after introductory words ('However, ...'), around non-essential information ('Dr Rao, our HOD, is on leave'), and between list items.
- Capital letters: sentence beginnings, proper nouns, days and months, the pronoun 'I'.
- Question mark only for direct questions: 'He asked where I lived.' (no question mark).
Quick example
Correct: 'its a known fact that the companys profit rose, however the share price fell.' Correct version: 'It's a known fact that the company's profit rose; however, the share price fell.' Changes: capital I; it's (it is); company's (possession); semicolon before 'however' to avoid a comma splice; comma after 'however'.
Common mistakes
- Using 'it's' for possession ('The phone and it's charger').
- Joining sentences with only a comma before 'however' or 'therefore'.
- Using apostrophes for simple plurals ('laptop's for sale').
How MU asks it
Asked as 'Punctuate the following passage/sentences' (3 to 5 marks) or within error-correction sets. Rewrite the full passage with capitals and marks in place; examiners check each mark, so do not change the wording.