1. 用括号内所给单词的适当形式填空

（1）—Is Grace your aunt?   

         —Yes, (her) is.

（2）Mike and Bob (be) friends.

（3）His (grandparent) are in Beijing.

（4）These are her (sister).

（5）—Are (this) your pencils?

         —No. My pencils are not black.