注意：此页面搜索的是所有试题
题目内容
（国家开放大学理工英语21）
For days, smog persisted in many areas. China is to control air pollution.
单选题 (10 分) 10分
A.
take measures
B.
doing business
C.
taking measures
单选题 (10 分) 10分
A.
take measures
B.
doing business
C.
taking measures
参考答案
