In recent years much more emphasis has been put developing the students productive skills

问题补充：

In recent years much more emphasis has been put developing the students productive skills.

A. onto

B. in

C. over

D. on

答案：

A. onto

B. in

C. over

(答案→)D. on

解析：put/ place/ lay emphasis on 是固定搭配，表示强调，注重。