Some people won’t realize the importance of their health ______ they have lost it.

Sometimes I feel bored and don’t  know ______ to do.                          

—________ is this blue shirt?—It’s seven dollars.

—What do you think of the book A Haw Tree written by a woman writer?—It reminds me of the days ________ I spent in the countryside. 

— ________ times a week do you go to the library? — Twice a week.