TCP/IP协议一共分为（）层。
A、3
B、5
C、7
D、9
参考答案：A
I have ______ my husband again and again not to smoke , but I can’t ______ him．
A．persuaded, advise
B．advised, persuade
C．suggested, persuade
D．suggested, advise
TD75型带式输送机槽角为（）。
A.20度
B.25度
C.30度
