Nowadays teens prefer going to the cybercafé ，_____ ,as is known to us, they can chat with their friends by QQ or play games.

There have been no occasions ____ he has come late for school.

An independent traveler would like to struggle with maps and signs ____ he finds the way．

—I'll call you ______ I arrive in Shenzhen． —Thanks, and good luck．

I had just taken a bite of my hot dog ________ I heard a familiar voice yelling at me from across the crowded school yard.