5. If he didn't have to pay father's debt, he wouldn't work overtime to get more money.
6. If everything weren't very expensive, city life would be enjoyable.
7. If there weren't industrial factories inside the city, pollution could be reduced.
8. If the sun didn't always shine, everything on the earch wouldn't grow well.
9. If there weren't a grammar error in this English composition, it could get a full mark.
10. If I had a typewriter, I could type it myself.
Học tốt