5．　　　　　　　　 He was doing his homework. Someone knocked at the door. (when)

4．　　　　　　　　 We will stay at home. It rains. (if)

3．　　　　　　　　 He studies English hard. He is over seventy. (though)

2．　　　　　　　　 He is too young to join the army. (so……that)

1．　　　　　　　　 He didn’t come. He was ill. (because)

10.　 Whatever ________ (happen) , I ________ (be) on your side.

9.　　　 　I hope you ________ (be) happy while you ________ (be)here.

8.　　　 　He ________(be) better today than he ________ (be) yesterday.

7.　　　 　Edison placed a big mirror behind the lamps so that the doctor ________ (operate).

6.　　　 　He ________ (leave) as soon as he ________ (drink) his coffee.