1. Make sure you back up your files.

2. The bus had to back up and turn round.

3. We trudged back up the hill.

4. The bus had to back up and turn around.

5. She looked back up the grassy slope.

6. The traffic is starting to back up on the M25.

7. Radio signals received from the galaxy's centre back up the black hole theory.

8. Back up a bit so that everyone can see.

9. The boat is pulling away,back up there!

10. He booted the ball 40 yards back up field.

10. Wish you can benefit from our online sentence dictionary and make progress every day!

11. The writer doesn't back up his opinions with examples.

12. You'll have to back up and turn around.

13. Make sure you back up every day.

14. You can back up another two metres or so.

15. You'll have to back up north.

16. Oil prices are coming back up .

17. That sort of attitude really gets my back up!

18. His offhand manner put my back up.

19. Some food labelling practices really get my back up.

20. These devices can back up the whole system.

21. We back up all the files every night.

22. You can back up another two feet or so.

23. Will you back up my story to the police?

24. There's no evidence to back up his accusations.

25. You can back up another two yards.

26. It's a good idea to back up your files onto floppy disk.

27. We back up our computer files at work on a daily basis.

28. She invoked several eminent scholars to back up her argument.

29. Life will knock us down, but we can choose whether or not to stand back up.

30. No matter how bad your heart has been broken, the world doesn't stop for your grief. The sun comes right back up the next day.