It is quite difficult

It is quite difficult

我选Atrain sb to do是教某人做什么的意思.(说实话,train的用法不熟,现在网上查的).至于to train,是因为it作形式主语,真正的主语是后面不定式.希望楼主给出答案,此题我也想知道答案.======以下答案可供参考======供参考答案1:Bit是形式主语，to引导真正的主语train sb. doing sth.吧供参考答案2:选B，练习it is to和have difficult doing供参考答案3:A Difficult to do something and you have to use to do something after him here供参考答案4:选B，it是形式主语，to不定式引导真正的主语，原句应该这么表达：To train him speaking English is difficult。可为了避免头重脚轻，所以才用it引导一个主语从句的。另外，本题还考察了train sb. doing sth （训练/教某人做什么）和be difficult to do sth（做什么事有困难）两个短语的用法供参考答案5:B

这个问题的回答的对