Cathy said she speak four languages.[ ]
A. may
B. could
C. would
D. can
答案：B
A．Fe2（SO4）3=2Fe+3+3SO4-2
B．CuCl2=Cu2++Cl2-
C．NaOH=Na++OH-
D．Ba（NO3）2=Ba2++2（NO3）2-
会计档案的定义是什么？
