the boy wants to go to the dentist ( to )clean teeth.

问题描述:

the boy wants to go to the dentist ( to )clean teeth.
为什么填to而不填for?

The boy wants to go to the dentist ( to ) clean teeth.这个男孩想去牙医那里清洁牙齿.因为这一空的后面是动词原形.to do是不定式,表示去牙医处的目的.for是介词,在它后面的动词是不能用原形的,必须改为doing形式,...