目前RRC CoNNeCtioN RequeSt后台配置重发次数为（）
A.1
B.2
C.3
D.4
参考答案：C
Go straight into the cave and find out what's in it, ________?[ ]
A. can't you
B. don't you
C. are you
D. will you
蛙类南游泳变态为两柄生活时，尾部会萎缩和退化，属于（）
A.神经性萎缩
B.营养小良性萎缩
C.废川性萎缩
D.压迫性萎缩
