He frinds----very hard to srudy English.A.they B.them c.it D

选C
这里是it做形式宾语,代替的是to study English.
如果换一种说法就是：He finds to study English very hard.
这里,to study English是宾语,very hard是宾语补足语.
要跟宾语从句区分清楚,如果是宾语从句,
为He finds(that)it is very hard to study English.(要多一个谓语动词is)
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