Every year lots of trees _______ to make our country more beautiful.[ ]

A．is planted

B．was planted

C．are planted

D．were planted

滑车神经支配的肌肉是（）

A．上斜肌 

B．下斜肌 

C．外直肌 

D．眼轮匝肌 

E．瞳孔开大肌