CS2B型号中，CS表示________、2表示______、B表示________。
参考答案：场效应器件、序号、区别代号
The computer doesn't work again. It __________.
A. need repairing
B. need to repair
C. needs repairing
D. needs to repair
（）信号提供接续的计费种类和主叫用户类别信息。
A.KA
B.Kc
C.KD
D.KE
