Use prepositions and articles accurately, and correct missing or wrong ones in editing

What this dot point is asking

Prepositions (in, on, at, to, for, of) and articles (a, an, the) are small words that carry a lot of weight, and they are among the errors the Editing task plants most often. Many are fixed by usage rather than by a tidy rule, so they reward learning the common patterns and noticing when a word is missing or wrong. This dot point covers the high-frequency preposition and article errors at O-Level and how to catch them when editing.

The answer

Articles: a, an and the

English has two kinds of article:

• "A" / "an" (indefinite) introduce any one of something, not yet identified: "I saw a dog." Use "an" before a vowel sound, not just a vowel letter: "an apple", "an hour" (the "h" is silent), but "a university" (the "u" sounds like "you").
• "The" (definite) points to a specific, known thing: "the dog next door", "the book you lent me".

Two common errors: dropping an article that is needed ("He is best student" should be "the best student", because superlatives take "the"), and using "a" before a vowel sound where "an" is required ("a hour" should be "an hour").

Prepositions of place

For place, the rough rule is size and enclosure:

• "At" for a specific point: "at the door", "at the bus stop", "at school".
• "On" for a surface or line: "on the table", "on the wall", "on the second floor".
• "In" for an enclosed space or area: "in the room", "in Singapore", "in the box".

A frequent error is "arrive to": you arrive at a place or arrive in a city or country, never "arrive to". Listening for the fixed pattern, rather than translating from another language, prevents most place-preposition slips.

Prepositions of time

For time the patterns are reliable enough to memorise:

• "At" for clock times and points: "at 3 p.m.", "at noon", "at night".
• "On" for days and dates: "on Monday", "on 5 June".
• "In" for longer periods, months, years and parts of the day: "in the morning", "in July", "in 2026".

So it is "in the morning" but "at night", and "on Monday morning" when a day is attached. These small differences are exactly what the Editing task tests.

Fixed combinations and editing

Many prepositions are fixed to particular words and must be learned as set phrases: "good at", "interested in", "depend on", "afraid of", "different from". There is little logic to memorise; the cure is reading and noticing. When editing, scan specifically for these small words: is an article missing before a noun, is "an" used before a vowel sound, does each preposition match its fixed partner and the place or time rules above?

Examples in context

Example 1. Time prepositions in one sentence. "Let us meet at the morning on 9 o'clock in Saturday" gets all three wrong. The corrections follow the rules: parts of the day take "in" ("in the morning"), clock times take "at" ("at 9 o'clock"), and days take "on" ("on Saturday"). The corrected sentence reads "Let us meet in the morning at 9 o'clock on Saturday." Because these patterns are fixed, the safest approach is to memorise the at/on/in trio for time and apply it mechanically, rather than guessing by ear.

Example 2. The missing article that changes meaning. Dropping an article can make writing read as non-standard and occasionally change the sense. "She is teacher" should be "She is a teacher" (any one teacher). "He plays piano" is acceptable, but "He is best player" must be "He is the best player", because the superlative needs "the". Noticing where a noun needs an article in front of it, and which article fits, is a quick win in the Editing task and lifts the accuracy of extended writing.

Try this

Q1. Correct this sentence: "He is good in football and afraid from dogs." [2 marks]

• Cue. The fixed pairs are "good at" and "afraid of": "He is good at football and afraid of dogs."

Q2. Give the correct time preposition for each: ____ the evening, ____ Tuesday, ____ midnight. [3 marks]

• Cue. "In the evening" (part of the day), "on Tuesday" (a day), "at midnight" (a clock point). The rule is in for longer periods and parts of the day, on for days, at for clock times.

Q3. Explain when to use "an" instead of "a", with two examples. [2 marks]

• Cue. Use "an" before a vowel sound (not just a vowel letter): "an apple", "an hour" (silent h), but "a university" (the u sounds like "you"). It is the sound, not the spelling, that decides.