资金汇划系统查询查复业务必须坚持（）的原则。
A.有疑必查
B.有查必复
C.查必彻底
D.复必详尽
参考答案：A, B, C, D
符号：断面收缩率（），冲击韧度（）。
E-mail, as well as the telephone, ___________ an important part in daily communication.
A．is playing
B．have played
C．are playing
D．play
