1. I’m busy, don’t __________ (打扰)me. 　　　　　　　　　　　　　　　

20. It is u_________ to tell it to him.

Unit 17

19. The manager c________ his business carefully.

18. Air is made up of nitrogen, oxygen, and other g______.

17. I have no d______ that he will pass the examination.

16. The five s______ are sight, hearing, smell, taste, and touch.

15. Water, milk and oil are l_________.

14. David suddenly lost　______of the car.

13. One day there was a　t_______ with lightning and heavy rain.

10. Make sure your pencils are s______ before we begin the test.

11 David decided to do an　e_______ to test 　his car.

12 Tom had changed the e______ in his car so that it would run on a mixture of　gas and normal fuel.