1、You'll crack up if you carry on working like this.
你再這樣干下去，身體會垮掉的。

2、Slot your foot into the crack up to the arch of your foot, keeping your knee out to the side.
把你的腳尖（大腳趾在上，小指在下）楔入裂縫中去，直到你的足弓的部分，膝蓋保持向外。

3、Suddenly without warning the plane seemed to crack up as it was about to take off.
飛機(jī)將要起飛時(shí)，突然，沒有得到任何警告，就好像要撞裂了。

crack up翻譯