Prepositions of time

years (in 1998)

days of the week (on Thursday)

hours of the clock (at 7.30)

months (in January)

dates (on 5 August)

religious festivals (at Easter)

seasons (in summer)

on Monday morning

points in time (at the end of the week)

parts of the day (in the afternoon, in the morning BUT at night)

We use during to talk about something that happens within a particular period of time, to say when something takes place.

We use during to talk about something that happens within the same time as another event.

During my time in London I visited a lot of interesting places.

He came to work during the morning meeting.

We use over or in to talk about something that has been happening continuously up until the present, or will happen continuously in the future.

We've had a lot of problems over / in the last few months.
We expect a rise in sales over / in the next few months.

We use for to say how long something continues.

I can only come for a few minutes.
I was waiting for him for two hours.

We use by to say that something will happen or be achieved before a particular time.

It has to be finished by two o'clock.
He should return by the end of March.

We use until to say that something will continue up to a particular time.

We have to stay here until he comes.
The concert went on until eleven o'clock.