Many trees on the hills last year. And we will plant more this year. A. plantB. plantedC.

问题补充：

Many trees on the hills last year. And we will plant more this year.

A. plant

B. planted

C. are planted

D. were planted

答案：

A. plant

B. planted

C. are planted

(答案→)D. were planted

解析：此题考查一般过去时的被动语态的基本结构。句意：去年在上山种了许多树。我们今年还要种植更多的树。结合语境可知上文描述的过去发生的动做，故用一般过去时态。主语是动作对象，故用被动语态，选D。