孩子们在看卡通片时笑得前仰后合。

The kids were ___laughing so hard while watching the cartoon.

孩子们看到小丑摔倒时都笑了起来。

The children started ___laughing when the clown tripped and fell.

他的新公司发展得很好，现在是他笑得最开心的时候。

With his new company thriving, he's the one ___laughing now.