Bài 3
1 did you often travel
2. tried  3:started 4.got, was waiting        5, did you learn      6. met-fell       7. started         8.were watching - was ringing     9.became     10.were playing-started
Bai 4:
1 have met    2. tried       3 have you received        4.stopped         5 have been                 6.have broken       7 has just come           8 have you been-came       9haven't seen- saw     10. hasn't drunk
P/S: nếu rảnh cậu qua giúp tớ bài toán nhé hihi. link nè:https://lazi.vn/edu/exercise/377282/cac-tia-phan-giac-aa1-va-bb1-cua-tam-giac-abc-cat-nhau-tai-i-thoa-man-ai-ibi