We planted trees last year.A. hundreds ofB. hundred ofC. five hundredsD. five hundred of

问题补充：

We planted trees last year.

A. hundreds of

B. hundred of

C. five hundreds

D. five hundred of

答案：

(答案→)A. hundreds of

B. hundred of

C. five hundreds

D. five hundred of

解析：hundred、thousand、million等数词与具体数字连用时，用单数形式，后面不加-s；若与of连用表示约数时，后面必须加-s，且不可与数词连用。hundreds of意为“成百上千的”，故选A。