Odpowiedź:
4.if you don't go out more often,you might fall ill.
5.unless you return this book to the library today you'll have to pay fine.
6.if he cleaned up the car now,his boss couldn't ask him to do this.
7.if they was absent now,they wouldn't meet the headmaster.
8.unless i know the number, i would not ring her up.
9.unless my sister have a terrible headache,she wouldn't be absent for her class.
10.unless Peter study hard, he could get good marks.
