题目: Whoever leaves the lab last, _____ all the lights are turned off.A.make sureB.make sure ofC.be sureD.be sure of 答案: 答案:A本题的含义是无论谁最后离开实验室,都要务必把所有的等关上,make sure表示务必或确保的意思,后跟从句,故本题选A。