1-5DDDCB　 6-10 B AB A B　 11-15CDBDA

15-20BCCDB

10.not until

1-5BDCCC 　　6-10A A B DB　 11-12BD

Grammar:

9.do

8.that

7. whose

6. which

5. used to isn’t used to

4. Although/Though

3. Whether

2. Upon finishing