New technology to make sure that the cars, taxis, buses and trains we use the air.
A. is used; not to pollute
B. has used; is not polluted
C. is being used; do not pollute
D. has been used; to pollute
网友回答
A. is used; not to pollute
B. has used; is not polluted
C. is being used; do not pollute
D. has been used; to pollute
解析：本题主要考查动词的时态及语态的应用。第 1 空强调目前所正在进行的一种行为。由于主语是动作的承受者，应该使用现在进行时的被动语态；第 2 空强调一般经常性的行为，应该用一般现在时。因此本题的正确答案选C。