大家同时举起了手。

Everyone raised their hands ___at ___once.

这个音乐节让我有机会同时看到许多乐队。

The festival gave me a chance to see many bands ___at ___once.

不要试图同时做所有事情——一步一步来。

Don't try to do everything ___at ___once - take it step by step.