Ex: Chia thì đúng cho các câu sau 1,It started to rain while I (walk)..................to school 2,She(not/finish)..................her homework yet 3,Nga and Lan (do)......................the homework at 8 o'clock last night 4,Oh dear! They always (go).................to class late 5,When Mr Tuan (arrive).................home , his children (watch)..............a film on TV 6,What...............you (do)..............at this time last Sunday ? We (collect).............waste paper for recycling 7,He (be)................in Viet Nam for two weeks 8,Yesterday Ba 9 (ask).................me to go to the station with him but I (not/want)................to leave the house because I (wait)...................for a call 9,I (already/see)....................that film 10,Mrs Quyen (do).................shoopping while Mr Thanh (attend).................a business meeting 11,Last night when we came to visit him,he (do)..................an experiment on the upstairs 12,Mr Ba (not go).................out since he has bought a new color television 13,They often go to school by bike,but yesterday they (walk).....................to school 14,We can't (go)..................out because it is raining now M.n giúp e vs ạ !!!! E cảm ơn !!!