- If you do something during something else, you do it at the same time.
- He often reads during dinner.
- I'm always tired because I work during the night.
- During tells you when something happens, not how long it takes. Compare:
- He read during dinner. (but we don't know how long he slept)
- He read for two hours. (but we don't know when he slept)
- During doesn't take -ing (present participial) complements. Compare:
- He read during dinner. (dinner is a noun phrase object)
- He read while eating dinner. (eating dinner is a present participial complement)