How are prepositions - 'for', 'while', 'during' used? - English Grammar lesson
Take the quiz - http://www.learnex.in/how-are-prepositions-for-while-during-used
We use 'for' followed by a period of time to say how long something goes on :-
Example - We watched TV for 2 hours last night
Example - I am going to Spain for 2 weeks.
We use 'during' followed by noun to say when something happens (not how long)
Example - Nobody was vocal during the presentation.
Example - I fell asleep during the film and I slept for an hour.
We use 'while' followed by a subject and verb.
Example - We saw sam while waiting for the bus.
Example - I fell asleep while watching TV.
Also when talking about future we sometimes use the present (not will) but the word 'while'.
Example - I will be in London next week, I hope to see John while I'm there.