In-Phrases — English Grammar Exercises
by mistake, on time, in advance — get the preposition right every time
In-Phrases in English
'In' phrases in fixed expressions most commonly place a person or thing inside a state or condition. The English Profile Programme corpus shows that 'in advance', 'in charge of', and 'in trouble' appear in the top 50 most tested prepositional phrases at B1–B2 level in major English exams. A frequent error with this group is substituting 'at' for 'in' ('at advance') or choosing the wrong complement preposition ('in charge about' instead of 'in charge of').
Core In-Phrases
in charge of — Who is in charge of the marketing department?
in danger — The old bridge is in danger of collapsing.
in a hurry — I can't stop now — I'm in a hurry!
in common — We have a lot in common — we both love hiking.
in trouble — If you miss that deadline, you'll be in trouble.
'In Charge Of' — The Complement Preposition
The thing you are responsible for always follows 'in charge of'. The prepositions 'about', 'for', or 'with' are incorrect here and a very common error.
Common Mistakes
✗ She is in charge about the project. → ✓ She is in charge of the project.
✗ I'm on a hurry. → ✓ I'm in a hurry.
Frequently Asked Questions
What is the difference between 'on time' and 'in time'?
'On time' means punctual — at the exact scheduled moment: 'The train arrived on time.' 'In time' means not too late — with enough time to spare, often implying it was a close call: 'We arrived in time to catch the last train.' A useful test: if you can replace the phrase with 'punctually', use 'on time'. If you can replace it with 'just in time' or 'before it was too late', use 'in time'.
What is the difference between 'for sale' and 'on sale'?
'For sale' means available to buy at its normal price: 'Is this house for sale?' 'On sale' means available at a reduced, discounted price: 'Winter coats are on sale — 40% off.' In British English, 'on sale' can also simply mean 'available in shops', but in the context of a discount, both British and American English use 'on sale'.
Why do we say 'by mistake' but 'on purpose'?
These are fixed idiomatic expressions with no logical rule — they must be learned as units. 'By mistake' and 'by accident' both describe unintentional actions ('by' here expresses manner or means). 'On purpose' describes intentional action ('on' here is part of a fixed set phrase). Speakers of Russian often confuse these because the Russian phrase «по ошибке» (by mistake) and «намеренно» (on purpose) do not map onto English prepositions predictably.
What is the difference between 'at the end' and 'in the end'?
'At the end' requires 'of' and refers to the final point of a specific, identifiable thing: 'At the end of the film, everyone cried.' 'In the end' means eventually or after a long process of deliberation — no 'of' follows: 'In the end, we decided to stay home.' A simple test: if you can follow it with 'of [something]', use 'at'. If it means 'eventually' or 'after everything', use 'in'.