46. Students are required _______ the project plan within a week.A. finishingB. to finishC. finishedD. finish

本题考查动词require的固定搭配用法。require作为及物动词，常见搭配为"require sb. to do sth."（要求某人做某事），其被动语态形式为"sb. be required to do sth."（某人被要求做某事）。题目中"Students are required..."为被动语态，空格处需要填入动词不定式to do形式，作主语的补足语，补充说明学生被要求做的动作。