during, at or in

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hello

These compounds prevailed during all developmental phases.
Is this sentence correct? Which is right? During phases, at phases or in phases.

Thanks

2

Hi.

‘During’ as a preposition indicates at times within a period but not necessarily the whole time. ‘In’ is less descriptive.

3

Sorry. But I don’t quite understand. Are ‘during’ and ‘in’ both acceptable in this sentence?

Thanks

4

I would prefer “during” .