In front of our teaching building_____.     A

        A.stand many tall trees           B.do many tall trees stand

        C.many trees are standing     D.many tall trees stands

  2.-why did you go back to the shop?    C

     -i left my friend_____there.

     A.wait  B.who waits  C.waiting   D.waited

 3.The country has already sent up three unmanned spacecraft,the most recent_____at the end of last          month.          B

    A.has been launched         B.having been launched   

    C.being launched               D.to be launched