1. 阅读下列短文，从每小题的三个选项中选出最佳选项。

1. （1） —Is the boy riding a bike?

   —               

   A . Yes, he is. B . No, he isn't. C . Yes, I am.
3. （2） Look at the three birds. They        now.

   A . are sing B . are singing C . singing
5. （3） —What are the dogs doing?

   —                

   A . They are sleeping. B . They are running. C . They are flying
7. （4） Which one is right (正确的)？

   A . The rabbit is eating. B . The girl is flying a kite in the park. C . The turtles (乌龟）are swimming in the water.