2.IF                                                                     ->UNLESS

1. if he does not pass the driving test , we will be disappointed

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2. i would not write to you if you did not send me your address

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3. if we do not protect the animals, they will be killed

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4. if jane does not apologize to us , we will not speak to her

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5. if people stop using dynamite for fishing , a lot of sea creatures will-preserved
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