15. I can't buy it ________ such a price.

14. -Are you ________ this proposal?

-No, I am ________ it.

13. There's no smoke ________ fire.

12. We have lessons every day ________ Saturday and Sunday.

11. The satellites go ________ the earth and help us to learn more ________ the earth.

10. My mother has been a teacher ________ 1986.

9. You have to go ________ the bridge and then you can see the hotel ________ your left.

8. Listen! Some birds are singing ________ the big tree.

7. He gave me two tickets ________ Saturday's evening show.

6. Their teacher is very strict ________ the students ________ everything.