X射线管中，高速电子所撞击的部位称为（）
A.阴极
B.阳极罩
C.阳极靶
D.发生器
参考答案：C
Professor Haley told me that he__________by many of his students at the railway station.
A．had been seen off
B．have been seen off
C．had seen off
D．have seen off
