=1-1/2+1/2-1/3+...+1/999-1/1000

=1-1/1000

=999/1000

1. Mai (not, see) doesn't see the plays very often.

2. He said he (not, know) didn't know her address.

3. Tomorrow when he comes we (go)will go shopping.

4. I (send) will send you a letter when I come to London next month.

5. ( not throw) Don't throw trash overthere.

6. Children must (take) take part in activities with others.

7. Did (You / come)you come to Ha Noi last month?

8. . How much does it (cost)cost to mail (mail) a letter to England ?

9. I prefer (chat)chatting with my friends.

10. She ought (study)to study hard.

Có thể phân biệt xenlulozơ với tinh bột nhờ phản ứng

A. với axit  H 2 SO 4

B. với kiềm

C. với dung dịch iot

D. thuỷ phân

câu b không cần làm à? Nguyễn Bùi Khánh Linh