演讲过程中，他停下来讲了个笑话来活跃气氛。

During the speech, he paused to ___crack ___a ___joke and lighten the mood.

他总是知道如何在恰当的时刻讲个笑话。

He always knows how to ___crack ___a ___joke at the right moment.

即使在紧张的谈判中，她也设法讲了个笑话来缓和局势。

Even in tense negotiations, she managed to ___crack ___a ___joke to defuse the situation.