英语必修5译林牛津版unit2培优测试及答案一．单项选择 1. for years scientists have been worried about the ___________ of air pollution on the earth’s natural conditions. a. effect b. result c. account d. cause 2. ___________ the problem of land erosion getting more serious, the government is searching for a way to deal with it. a. as b. with c. when d. if 3. i first met john at my sister’s wedding. he ___ with the bridegroom at the time. a. talked
