乐队在正式演出前进行了三次彩排。

The band had three ___rehearsals before the actual performance.

我们必须在演出前进行多次彩排。

We need to have several ___rehearsals before the performance.

她在考试前默默把重要公式在脑海里过了一遍。

She did a silent ___rehearsal of the key formulas before the exam.