下列哪种X线不属于普通X线机()
A．临界X线机
B．接触X线机
C．浅层X线机
D．中层X线机
E．深层X线机
参考答案：D
My teacher made me ____ at school yesterday because I didn't do [ ]
A. stayed
B. stay
C. to stay
D. staying
猪传染病是如何发生的？怎样预防？
