I _________ a little English before I went to Singapore.A. study; B. had studied

1.I _________ a little English before I went to Singapore.
A. study     B. had studied    C. had study    D. have studied  
2. Before I went to bed, I _________ my teeth.
A. have brushed  B. had brushed  C. brushed  D. brush 
3. Before my mother came home, my brother _________ food on the table.
A. had prepared  B. have prepared  C. prepared  D. had prepare
4. I watched movie after I _________ my homework.
A. have completed  B. had complete  C. had completed             D. completed  
5. Alice _________ a Vietnamese person until he met Nam
  A. had never met         B. have never met        C. never met                     D. never have met