1 we started learning english when we were in grade 3 
-> we have .........
2 ba doesn't learn hard so his marks at school are always bad
-> if....
3 "pleasse, come to see us when never you have free time ,marry." daisy said 
-> daisy inveted ... 
4 the children are listening to music in their room 
-> music .........
5 I have read book twice because it is very interesting 
-> this book
6 minh won' t pass the final exam if he doesn't learn hardeer 
-> unless ........
7 scientists have reported that there is far too much pollution nowadays in city areas 
-> it ...........
8 my sister likes reading books better than watching IV in her free time 
-> my sister ............
9 my mother sometimes wants to come back to her childhood 
-> my mother sometimes wishes she ...............
10 if we don't learn harder, exam we will not pass the final 
-> uless ..........
11 every student must obey the school regulatios 
-> the school regulatios .........
12 there were many lakes in our village, but now there are only a few
-> our village used ...........