20.　 　Many new scientific d__________ were made by chance.

Unit 20

19.　 　I sowed some sunflower s________ in the backyard.

18.　 　He invented a new ________ of teaching English.

17.　 　He p_______ water out of the flooded building.

16.　 　The pianist has t_________ skill but not much feeling.

15.　 　A teacher is often compared to a __________(园丁).

14.　 　Teachers with _________ (实践的) experience are badly needed in this school.

13.　 　Our success d________ on whether everyone works hard or not.

12.　 　He is a man of _______(智慧).

11.　 　How has agricultural _________ (产品) changed during these years?