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

A．onto

B．in

C．over

D．On

（）不是眼睑的作用。

A、可致生理性散光

B、防止泪液过度蒸发

C、泪液展开

D、其下垂可导致形觉剥夺性弱视