17)
1.because
2.but
3.but
4.and
18)
1.The Watsons aren't having barbecue because it is raining.
2.Ben leaves his job at 5 o'clock and he catches the train to go home.
3.You could say she leads a double life because she has two jobs.
4.Mary loves her job but she doesn't like working on Sundays.