— How is it going, John?
—
A:It's fine today.
B:It's Sunday today.
C:Everything goes well, thanks.
D:Have a good time!
张大爷家养了3头牛和20头猪,如果1头牛的质量相当于5头猪的质量,那么牛和猪的总质量相当于____ 头牛的质量,或者相当于____ 猪的质量。
通过实验,将带叶枝条插入红墨水后,枝条被染红的结构是( )