问题补充:
-- The city of Wenzhou looks more and more beautiful.
-- Yes. That’s because lots of trees every year.
A. plant
B. are planting
C. are planted
D. have planted
答案:
A. plant
B. are planting
(答案→)C. are planted
D. have planted
解析:句意:温州市看起来越来越漂亮了。——是的。那是因为每年都要种植许多树。结合语境可知下文宾语从句中表示的是客观性的动作,故用一般现在时态。主语是动作对象,故用被动语态,选C。