English learners often struggle with the use of prepositions in expressions such as: On time / in time; At the end / in the end;
On time – means exactly on time, not later. The event happens at the precisely planned time.
The 11.45 train left ON TIME. (= IT LEFT AT 11.45)
The train at 11.45 left on time. (at 11.45)
Please, be there ON TIME. (= don't be late / be there at 7.30)
In time – soon enough to do something;
Will you be at home IN TIME for dinner? (= soon enough for dinner);
However: if we add 'just', the meaning is again 'exactly on time'
We got to the station JUST IN TIME to catch the train.
At the end (of something) – the time when something finishes.
at the end of the month / at the end of the film / at the end of January;
I'm going away at the end of January.
The opposite of 'at the end' is 'at the beginning' (The opposite expression of 'at the end' is 'at the beginning');
at the beginning of the concert / of January;
In the end = finally – we use it when saying what the final result of a particular situation was;
Tom couldn't decide where to go for his holidays. He decided to go to Italy in the end.