These prepositions explain a period of time in which an event, activity or situation took place:

e.g. during the next month while I was swimming.

 Structure: During:

during + a noun or phrase: the war, the nineteenth century: e.g. during my schooldays. This phrase can be used with all verb tenses: past, present, future.

e.g. Magda received many telephone messages during the last week. - past

I am seeing Simon during the morning. - present

Winston will return to England during the Christmas Holiday. - future

Structure: While:

while + subject + verb: to eat, talk, swim, walk etc.... This clause can be used with all verb tenses: past, present, future

e.g. We will take you to the theatre while we are in London.

While Joanna was in Spain, she didn't go to a bull fight.

N.B. In English, While can often be replaced by when and retain the same meaning.

while + infinitive + -ing (Present Participle): thinking, running, driving etc..

e.g. While swimming in the sea, Hania was attacked by a shark.

Ela met Andrew while studying English at Oxford.