下列对1045交易描述正确的是（）。
A、转出方账户必须有折
B、转入方账户必须有折
C、转出方账户必须无折
D、转入方账户必须无折
参考答案：D
A poet and artist _____ coming to speak to us about Chinese literature and painting tomorrow afternoon. [ ]
A. is
B. are
C. was
D. were
丝锥是用于铰制管路附件和一般机件上的（）的专用工具。
A、钻孔
B、外螺纹
C、内螺纹
D、切削
