How long have you ______ this book ?

It is foggy(多雾的) today. The plane can't       .

— Linda，I am very thirsty.—Let’s go to the nearest supermarket          some drink, OK?

Trees provide food and shelter and make us ______ comfortable.

Smoking is not allowed in public places since May 1st. It may be a good chance for some people to ______ smoking.