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4. A person cannot travel abroad unless she/he has a passport.
5. If Ann hadn't lost her passport last week, she wouldn't be having a lot of trouble .
6. Unless you tell him what to do, Tom doesn't do anything.
7. Unless we take steps to preserve natural resources, the planet will be in danger.

8. If only your sister could come as well.
9. If the farmer didn't add fertilizers, the soild wouldn't become poor.
10. If only you had time to come and see me.
11. Had there not been such a lot of traffic, we wouldn't be late.
12. If you hadn't helped me, I couldn't have managed it.
13. If she had been less determined she wouldn't have been able to get better so quickly.

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