10. It is very hot today, please keep the window__.

A. opening     B. open    C. opens    D. to open

11. --May I play with my dog?

   --I am afraid not. You can’t play with it __ you finish your homework

A. when    B. until     C.after     D. because

12. I am afraid I won’t __ finish reading the book in two days

A. can     B. could   C. be able to    D. may