Fixed Prepositional Phrases — Test Questions
Six mixed questions on by mistake, on purpose, in charge of, on time, at least, and in the end — idiomatic expressions that don't follow a general preposition rule.
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I took your pen ___ mistake — here it is.
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by
'By mistake' — a fixed expression meaning 'not on purpose'.
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He did it ___ purpose to annoy her.
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on
'On purpose' — a fixed expression meaning 'intentionally'.
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She's ___ charge of the marketing department.
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in
'In charge of' — a fixed expression meaning 'responsible for'.
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The plane was due to arrive at 5:15 and it landed right ___ time.
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on
'On time' = at the scheduled time, punctual.
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It will take about three hours to do this work, at ___.
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least
'At least' = minimum, no fewer than.
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___, we decided to cancel the trip because of the weather.
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In the end
'In the end' = eventually, after considering everything. 'At the end' needs 'of' + something specific.
Fixed Prepositional Phrases: What This Test Checks
Fixed prepositional phrases carry a preposition assigned by convention rather than by any spatial or logical pattern, which is exactly what makes this category so error-prone: a learner can know every general preposition rule perfectly and still get these wrong, because there is no rule to derive them from — only memorisation of the whole unit. 'By mistake' (accidentally) and 'on purpose' (intentionally) form a natural opposing pair that this test checks together, since learners who get one right often assume the other must share its preposition, producing 'on mistake' or 'by purpose'.
'In charge of' means responsible for, and keeps 'in' regardless of what follows ('in charge of the marketing department'). 'On time' means punctual, at the exact scheduled moment — distinct from 'in time', which means early enough to make it before a deadline, a subtle contrast this test isolates by testing 'on time' in a context describing an exact scheduled arrival. 'At least' states a stated minimum quantity, easily confused with the unrelated 'at last' (finally) because the words are one letter apart. 'In the end' means eventually, after weighing up a whole situation, and is distinct from 'at the end of', which always requires a following noun phrase ('at the end of the street') and cannot stand alone as a complete phrase the way 'in the end' can.
He did it on purpose to annoy her. (intentionally)
She's in charge of the marketing department. (responsible for)
In the end, we decided to cancel the trip. (eventually, after considering everything)
Last updated: · Satori Editorial