For and during: uses and examples
"For" and "during" are both prepositions that are used with expressions of time.
For is used with a period of time, and describes the length of time it takes for something to happen:
"We watched TV for three hours last night."
"I'm going on holiday for a week."
"I've been waiting for a long time."
During is used before a noun, and explains when something happens. It cannot be used to express how long something happens for. When you use the word during, you are talking about two things that happened at the same time, for example:
"I fell asleep during the film." (Sleeping happened at the same time as watching the film.)
"Many questions were asked during the discussion." (Questions were asked at the same time as the presentation took place.)
"We will be on holiday during the summer." (The holiday and the summer take place at the same time.)
During and while: uses and examples
While is similar to during, in that it refers to two things that happen at the same time. However, it requires a different sentence structure. During is followed by a noun, but while must be followed by subject + verb. The length of time, in this case, is not important.
|"The telephone rang during the TV programme." (during + noun)||"The telephone rang while I was watching TV." (while + subject + verb)|
|"I listened to music during my study." (during + noun)||"I listened to music while studying." (while + subject + verb)|
|"The students took notes during the lecture." (during + noun)||"The students took notes while the teacher was speaking." (while + subject + verb)|
For and during: be careful!
When using while to talk about future activities, be sure to use the present, rather than future, tense.
So, "I hope to see Tom while I'm in London" is correct, and "I hope to see Tom while I will be in London" is incorrect.