-Our city looks more beautiful!-Yes. Lots of trees and grass since last year.A. have been

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。