Why don’t you answer my question, Bill? —difficult for me to answer. [ ]

______ can you walk in one hour?—Six kilometers.[ ]

_______ useful tool the computer is!— I agree. It’s ________ interesting as well.

I’m afraid you ________play basketball here.— I’m sorry I won’t.

What do you think of Confucius?—He wasan ancient teacher ______ wise sayings haveinfluenced many people in different countries.