单选题 ______the assignments are turned in before the end of this week.
【正确答案】 D
【答案解析】解析：A项see it that不是固定短语；B项make sure that“务必，一定”，但是make itsure that不是固定短语；C项assure“保证”，其宾语是人，不能是that：D项see that“务必，保证”。