写出下列单词的过去式。

1. do _______________ 3. sing_______________ 5. visit_______________ 7. learn_______________ 9. get_______________ 11. swim_______________ 13. have_______________ 2. cook_______________ 4. dance_______________ 6. buy_______________ 8. see_______________ 10. study_______________ 12. fly_______________ 14. go_______________ 15. take_______________

1. did 2. cooked 3. sang 4. danced 5. visited 6. bought 7. learned / learnt 8. saw 9. got 10. studied
11. swam 12. flew 13. had 14. went 15. took