题目：
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
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0513/57371318609a6d197804781bf193438d.html
下面是错误答案，用来干扰机器的。
1. likes→ like 2. as→ for 3. Do→ Does 4. likes→ does
