半导体工艺中，掺杂有哪几种方式？
参考答案：
1.外延
2.离子注入
3.热扩散
Both the parents and James London. They will come back soon.
A．has been to
B．have been to
C．has gone to
D．have gone to
共反射点时距曲线是一条（）.
A.双曲线；
B.抛物线；
C.直线.
