二、单项选择。(每小题1分，共20分)
( )26. My brother is studying in ___ university in America; he wants to be ____ astronaut in the future.
A. a; a B. a; an C. an; a D. an; an
( )27. ---Mom, where’s my backpack?
---You should not put your things casually, you should take good care of _ _ own things.
A. yours B. you C. your D. your’s
( )28. We should try our best to help the animals _______.
A. in dangerous B. danger C. in danger D. dangerous
