Customers are asked to make sure that they ____ the right change before leaving

题型：不详难度：来源：

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

B

解析

试题分析：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
点评：做时态题时，首先看时间状语，由时间状语来确定句子的时态；如果没有时间状语，可以根据隐含的意思来确定句子时态。