三极管的发射极用英文字母()表示.
A、B;
B、C;
C、E;
D、S
参考答案:C
-- I called you this morning, but nobody answered it.
-- Oh, we ______ some shopping at the supermarket.
A.are doing
B.were doing
C.have done
D.did
下面属于Class的方法有( )。
A.public class getName()
B.public classLoader getClassLoader()
C.public class getComponentType()
D.以上答案都正确