【题目】—You've made great progress in your studies of English, haven't you?
—Yes, but much.
A.remains to do
B.is reminded to
C.remains to be done
D.is remained to be done

【答案】C
【解析】句意：我虽然取得了进步，但是还有很多需要去做。remain是不及物动词，没有被动语态。那就是说这些需要做的事情是被我去做，要用被动表示，所以只能用to be done体现，故选C。