问题补充:
Many flowers in our school last year,and they made our school a beautiful garden.
A. plant
B. planted
C. have planted
D. were planted
答案:
A. plant
B. planted
C. have planted
(答案→)D. were planted
解析:句意:我们学校去年种了很多花,它们使学校变成了美丽的花园。主语是flowers花,与动词plant种植是被动关系,所以用被动语态,结构为:be+动词过去分词;从last year得知是过去的事情,所以用were planted,故选D。