(   ) 1. Mr Li taught me      in the river when I was a child.
  A. to swim       B. swam      C. swimming      D. swims
(   ) 2. On National Day there are more than four      people in the park. 
  A. thousand     B. thousands     C. thousands of     D. thousand of
(   ) 3. Last month I went to a small village      I was born. 
  A. when      B. what      C. how      D. where
(   )4. He had to put his shoes lightly,      he?
  A. didn't     B. did     C. had     D. hadn't