In extremely poor societies, children can be put to work ____ a young age and are therefore a source of income.
- (a)in
- (b)on
- (c)by
- (d)at
Correct — D, at. This is a preposition-cloze item. English fixes the phrase 'at a young age' (and 'at the age of...') to state the point in life when something happens, so 'put to work at a young age' is the standard form.
- (a)in — 'In' works for broad periods ('in childhood', 'in his youth') but not with the countable phrase 'a young age', which takes 'at'.
- (b)on — 'On' is used for days and dates ('on Monday'), not for stating someone's age.
- (c)by — 'By a young age' would mean 'no later than', changing the meaning; the sentence needs the point in time, which is 'at'.
This is a preposition-cloze item — the point in life is marked by 'at' in the fixed phrase 'at a young age' / 'at the age of...'.
No directly related past PYQ was found.
- practice — not a real PYQ
Fill in the blank: 'She learned to read ____ the age of four.'
- (a)in
- (b)on
- (c)at
- (d)by
Answer(c) at — 'at the age of...' is the fixed phrase for a point in life.
- practice — not a real PYQ
Fill in the blank: 'He started training ____ an early age.'
- (a)at
- (b)in
- (c)on
- (d)to
Answer(a) at — the countable phrase 'an early age' takes 'at'.