You _____drive your car so fast.It's very dangerous.

问题描述:

You _____drive your car so fast.It's very dangerous.
A.wouldn't B.shouldn' C.couldn't D.mightn't .教材里的答案是B,为什么不能是C.

从意思和语气上来理解,shouldn't表示不应该,还带有点责备教训的意思;而couldn't意为不能,表示禁止做某事.
其实情态动词的题我觉得最重要的是语感,有很多细微的理论差别根本记不住.