-Can I _____ your sister?
-Hold on, please. [ ]
A. speak
B. speak to
C. talk
答案:B
下列记账凭证中可以不附原始凭证的是( )。
A.所有收款凭证
B.所有付款凭证
C.所有转账凭证
D.期末账户结账的记账凭证
微分方程(x2-1)dy+(2xy-cosx)dx=0满足初始条件的特解为______.