1.He didn't want to answer the telephone ___ ___ ___ (当着……的面)his friends.
2.You are often late for school you should ___ ___ ___ ___(为自己感到害臊).
3.This kind of mobile phone is ___ ___ ___(落后于时代了)
4.Now he had become an expret ___ ___ ___(快速发送)messages.