.How long do you think______ the construction company finishes the project?

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

Look at ______ book on the desk . Is it ______ useful one ?–Yes, it is . In the book there is much advice on how to learn math well.

Do you know the teacher ____ classes are interesting and exciting?— Yes, she is Mrs. Zhang.

What’s this ____________? — It is a map.