逆转录
参考答案:以RNA为模板合成DNA的过程。
With all his attention ____ on the computer game, the boy even didn't notice his mother came in.
A.was fixing
B.was fixed
C.fixing
D.fixed
《喂——出来》作者在文章结尾设计“声音”、“石子”又回来了,有怎样的用意?
答:________________________________________________