即时通信系统一般采用中转模式和______两种通信模式。
参考答案：P2P模式
Getting rid of bad habit is________forming a good one. [ ]
A. an effort much as
B. much an effort as
C. as an effort much as
D. as much an effort as
下列癌在胃幽门部一般不会出现的是（）。
A.腺癌
B.鳞状细胞癌
C.硬癌
D.胶样癌
E.髓样癌
