通常单纱的捻向为（）捻，股线为（）捻。
参考答案：Z；S
Before building a house, you will have to ____ the government's permission. [ ]
A. get from
B. follow
C. receive
D. ask for
三极管的三个电极是（）
A、基极、发射极、集电极
B、基极、阳极、阴极
C、门极、阳极、阴极
D、门极、发射极、集电极
