They have some problems ____ for the party.A, prepare B, to prepare C, prepared D, preparing答案是D,怎么解释?
问题描述：
They have some problems ____ for the party.
A, prepare B, to prepare C, prepared D, preparing
答案是D,怎么解释?
答
have difficult / problem (in) doing sth
意思是做什么事情有困难，In 通常省略
答
have some problems (on) doing sth
做什么事情遇到了点麻烦。一般on省略
答
have problems in doing something
在做.的时候有麻烦或者问题,但是介词in一般省略,所以选最后一个
答
Have problems或Difficulties in doing sth,其中介词In可省略,肯定正确的。