粗化应在（）
A.制版后
B.制版前
C.网布织造时
D.被印物印前
参考答案：B
In one's life, it doesn't matter how many friends you have, but getting _____ understanding you is enough. [ ]
A. it
B. one
C. them
D. another
5.6克不纯净的铁片与足量的稀盐酸反应放出0.21克H2则原铁片中含有的金属杂质为（ ）
A．Zn
B．Mg
C．Cu
D．Pb
