It is because English is very useful_____A.at which we work hard B.that we work hard at itC.which we work hard at D.wjich we work hard
问题描述：
It is because English is very useful_____
A.at which we work hard B.that we work hard at it
C.which we work hard at D.wjich we work hard
答
B
答
a
答
B 吧..这个句子是强调句啊!It is because English is very useful that we work hard at it.[强调句：It is/ was + 被强调部分（通常是主语、宾语或状语）+ that/ who（当强调主语且主语指人）+ 其它部分.]强调句还...
答
B It在这里是形式主语，而that引导的从句才是真正的主语。这句话如果直译的话应该是这样的：我们刻苦学习英语是因为英语很难。