21. (   )— Do you know _________ this iphone5 belongs to?

   — Let me see. Oh, it’s __________.

       A. whose; her           B. whose; hers        C. who; her            D. who; hers

(   ) 22. — I always get nervous when I start a(n) _________ with others.

   —Take it easy. Believe in yourself.

       A. expression           B. introduction           C. communication      D. celebration