Lucy,I can easily ______ your smiling face that the news is good.
A:refer to
B:find out
C:tell by
D:talk about
如图为植物体某些生理过程的概念图,据图回答问题:
鲫鱼的口和鳃盖后缘不停地相互交替张开和紧闭,其作用是( )