问题补充:
-Our city looks more beautiful!
-Yes. Lots of trees and grass since last year.
A. have been planted
B. are planted
C. will be planted
D. were planted
答案:
(答案→)A. have been planted
B. are planted
C. will be planted
D. were planted
解析:根据 since last year可知,本句应该是现在完成时。本句的意思是“自从去年,许多树和草被种了。”所以本题选A。