chuyển sang câu bị động
1 they must widen the road soon
2 my sister cleans these rooms everyday
3 wastes from chemical factories have caused a lot of pollution
4 when does he usually do his homework?

1 somebody must send for the doctor as soon as possible
2 we will grow a lot of trees in the parks
3 somebody will meet you at the bus station
4 you mustn't use this machine after at 5.30
5 he asked us many difficult questions
6 she advised me to reuse milk bottles
chuyển sang câu bị động

từ "được", " đã được " có được coi là từ nối giữa các câu vế của câu ghép không?