单词拼写。

1 ．Scientists have made many important_______ (发现)．

2.An____ (突然的)change of policy made everything up.

3 ．The store sells agricultural______ (产品)．

4.I keep my reference books near my desk for_______ (方便)．

5. He ate a light lunch in____ (期望)of a good dinner.

6. He likes inventions and he has applied for a p____ .

7. I've never seen so much m_____  and disorder.

8. It's an interesting idea but there are many p  _____  difficulties.

9. As _____   world is essential to economic growth.

10. He goes to visit his grandparents not regularly but o _____   .