—What are you supposed to do while chatting with friends on the Internet so that the other person doesn't        ?

—You are supposed to type quickly.[ ]

A. become annoying    

B. feel boring    

C. get bored    

D. get used to it

营地选择原则（）。

A.水源补给

B.营地平整

C.背风背阴

D.远离危险