问题补充:
Customers are asked to make sure that they the right change before leaving the shop.
A. will give
B. have been given
C. have given
D. will be given
答案:
A. will give
(答案→)B. have been given
C. have given
D. will be given
解析:考查时态,由后面的句子before leaving the shop.可以知道动作已经完成,所以用完成时,they和动词give是动宾关系,所以用被动式,句子意思“消费者被要求离开商店之前做出正确改变”, make sure固定词组“确保”,后面跟从句,所以选B