某病人肢体震颤，闭目站立不稳，不能完成精巧动作，他的病变部位是 [ ]
A．大脑
B．小脑
C．脑干
D．脊髓
答案：B
About two years ________ since the earthquake took place in Wenchuan.
A．passed
B． has passed
C．have passed
D．has been passed
偏振光
