存取时间是指( )。A．存储器的读出时间 B．存储器进行连续读和写操作所允许的最短时

观察鸟的形态结构示意图，请结合图示写出鸟类适于飞行生活的特点

（1）外部形态：______．

（2）骨骼和肌肉：______．

（3）呼吸：______．

The ABC Bank Irrevocable documentary credit Number: LC123-258866 Date: August 24,1999 Date and place of expiry : October 30, 1999 China Advising bank: Bank of China Beneficiary: China XYZ import and export corp. Applicant: UVW corporation. Amount: USD52,500 (Say U.S Dollars fifty two thousand five hundred only) We hereby issue irrevocable documentary credit which is available with: Any bank By negotiation of beneficiary’s drafts at sight For full invoice value Drawn on the ABC bank Partial shipments: Not allowed Transshipment: Not allowed Shipment from: Shanghai To: Tokyo Japan At the latest: October 15, 1999 Following documents required: +Signed commercial invoice in three copies +Full set of clean on board ocean bill of lading +Weight certificate in two copies Covering: 100 metric tons (5PCT MOL) of XY chemical in drums at USD 500 per M/T. Special instructions: Insurance to be effected by buyer. Instructions to advising bank: Please advise this credit to the beneficiary We hereby undertake that drawers, endorsers in compliance with the terms of this credit will be duly honored upon presentation to the drawee bank. Authorized signature 一、根据上述信用证，回答下列问题

信用证的最高金额

公安机关的任务是一个多形式、多层次的系统，其中，从范围上分，包括( )。

A．局部任务和全局任务

B．目前任务和长远任务

C．中期任务和远期任务

D．基本任务和具体任务

雷达接收机通常用（）来表示接收机接收微弱信号的能力。

下列关于报关单位和报关员关系的理解错误的是：

A．取得报关员资格证书的人员必须受聘于某个报关单位，且由其所在报关单位为其向海关办理注册登记后才能成为报关员
B．报关单位的进出口报关事宜应由报关员代表本单位向海关办理
C．报关员经所在企业授权发生的报关行为，其法律责任应由报关员承担
D．对脱离报关员工作岗位和被企业解聘的报关员，报关单位应及时收回其报关员证件，交海关办理注销手续，因未办理注销手续而发生的法律责任由报关单位承担