To make the city beautiful a lot of flowers and trees every spring.A. plantB. are plante

问题补充：

To make the city beautiful, a lot of flowers and trees every spring.

A. plant

B. are planted

C. planted

D. were planted

答案：

A. plant

(答案→)B. are planted

C. planted

D. were planted

解析：句意:为了让城市变漂亮，每年春天都会种很多的花和树。plant 在这里是一个动词，意思是种植。根据句意可知，每年春天都会种花，种树，所以这个句子应该用一般现在时；故排除C和D。又根据句意可知，这里的主语flowers and trees和动词plant之间是被动的关系，应该用被动语态。故选B。