6．下列表示溶液中发生反应的化学方程式错误的是(　　 )

A．2Al+2NaOH+2H₂O＝2NaAlO­₂+3H₂↑

B．KMnO­₄+HCOOK+KOH＝2K₂MnO₄+CO₂↑+H₂O

C．MnO₂+4HCl(浓) MnCl₂+Cl₂↑+2H₂O

D．K₂Cr₂O₇+6FeSO₄+7H₂SO₄＝Cr₂(SO₄)₃+3Fe₂(SO₄)₃+K₂SO₄+7H₂O

20.--Do you have ______ homework?

　--I don’t have ______.

　A. some, some B. some, any

19.“Help _______ to some cakes!” Uncle Tom said to the twins.

　A. yourself B. youself

　C. yourselves D. youselves

18.--_______ of the dictionaries would you like?

　--I’ll take _______ of them, so I can give one to my cousin.

　A. Which, both B. Which, all

　C. What, either D. What, both

17.The buildings in Dalian are similar to ______ in Tokyo.

　A. ones B. those C. these D. that

16.--What are you doing here, Mary and Kate?

　--We are looking at _______ pictures.

　A. each’s other B. each other’s

　C. each other D. each’s other’s

15.I have had enough food. Would you like _______?

　A. a few more B. one more

　C. another more D. some more

14.She stayed at this school longer than ______.

　A. anyoneB. everyone

　C. anybody else D. else anyone

13.The book on the shelf is ______. She wrote her name on ______ cover ______

　A. her, it, herself

　B. hers, it, herself

　C. hers, her, herself

　D. hers, its, herself

12.We think ______ important to protect the environment.

　A. it B. this C. that D. what