Whitney Houston’s sudden death suggests that drug abuse is such a serious problem ______ we shoulddeal with properly.[ ]

We won’t ______for delivery if you pay now

idn’t find the name of the boy in the list, ________， of course, made them very disappointed.

I first met Lisa three years ago. She ________ at a radio shop at the time.

You can’t imagine ____ fantastic fun web chatting is.——Really? But it may cause a lot of trouble sometimes.