一  单项选择（每小题1分，共15分）

（   ）1.We can have _______bluer sky if we create _________ less polluted world.

A. a; a        B. a; the      C. the; a       D .the; the

(    )  2. ―Look! _____ clean the river looks !

     ―Yes. I’m sure somebody _____ it up.

A. What; has cleaned   B. How; has cleaned   C. What; cleaned   D. How; cleane（   ）

3 . ―Paul invited us to go on a trip to Jiming Temple tomorrow.

―______? Have the Flowering Cherries(樱花) on each side of the roads come out?

A. Why not?           B. What for?        C. What time?               D. Who else?