You are creating a Windows Forms application for a courier company by using the .NET Framework 3.5.You create a form that allows customers to track the progress of their shipments.The form contains the following elements: (1)A text box named txtTN that allows users to enter a tracking number. (2)An ErrorProvider control named ErrorProvider1 that informs users of an invalid tracking number. (3)A function named ValidTrackingNumber that validates tracking numbers. You need to ensure that the txtTN text box is validated. Which code segment should you use?() ["A","B","C","D"]
关于公安机关向被处罚人送达《治安管理处罚决定书》的方式,表述不正确的有()。 ["公安机关只有在无法直接送达的情况下,才能采用其他送达方式","在委托送达中,作出处罚决定的公安机关可以委托被处罚人居住地的公安机关代为送达","邮寄送达中,挂号凭证即为送达凭证","公告送达以30日为限"]
流动介质为酸或碱的管道的颜色标准编号()。 ["P02","YR05","无","PB06"]
除专用合同条款另有约定外,发包人应在签发竣工付款证书后的14天内,完成对承包人的竣工付款。发包人逾期支付超过56天的,按照中国人民银行发布的同期同类()的两倍支付违约金。 ["贷款基准利率","贷款基准利率的两倍","贷款基准利率的三倍","存款基准利率的两倍"]
根据汽车行驶方程可知,当汽车要加速行驶时,汽车驱动力与行驶阻力的关系应是()。 ["Ft<\/sub>=Ff<\/sub>+Fi<\/sub>+Fw<\/sub>+Fj<\/sub>","Ft<\/sub>>Ff<\/sub>+Fi<\/sub>+Fw<\/sub>+Fj<\/sub>","Ft<\/sub><f+Fi<\/sub>+Fw<\/sub>+Fj<\/sub>","Ft<\/sub>≠Ff<\/sub>+Fi<\/sub>+Fw<\/sub>+Fj<\/sub><\/f"]
1301室内灭火时操作法?