During or While

We use during + noun to say when something happens. We don’t write a period of time with it.
We use while + subject + verb to talk about two things that happen at the same time. The events don’t have to continue for the same length of time, but they can.

  • He fell asleep during three hours.
    (Wrong, don’t use a time period.)
  • He fell asleep during the presentation.
    (Correct, when something happens.)
  • During the winter we get a lot of snow.
  • The kitten fell asleep while eating its dinner.
    (Correct, two things happened at the same time.)
  • I read a book while Josie listened to the radio.