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【单选题】
关于电磁波和超声波的知识,下列说法中正确的是(  )
A.
超声波和微波的传播一定要有介质
B.
超声波和紫外线都能传递能量
C.
超声波可用于清洁物品,无线电波既可用于清洁物品又可用于卫星通信
D.
超声波在不同介质中传播速度相同,所有电磁波在真空中传播速度都是3×10 8 m/s
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【单选题】He orders me about ______ my boss.
A.
as he is
B.
as if he be
C.
as if he were
D.
as if to be
【单选题】____, he would have passed the exam.
A.
If he were to study
B.
If he studied hard
C.
Had he studied hard
D.
Should he study hard
【单选题】在 Internet 中传输控制协议 / 用户数据报文协议是 ____________ 。
A.
TCP/ UDP
B.
TCP/IP
C.
IP/ICMP
D.
Telnet/SMTP
【单选题】_____ yesterday, I would have asked him not to do that. A. If he had come B. Provided he came C. If he came D. If he has come
A.
If he had come
B.
Provided he came
C.
If he came
D.
If he has come
【多选题】关于共同配送,下列说法正确的是( )。
A.
由多个企业联合组织实施的配送活动
B.
外包给专业化的物流企业
C.
可分为同企业共同配送、异产业间的横向共同配送和纵向配送
D.
可提高单车装载率,容易导致交错运输
【判断题】《物流术语》对共同配送的定义是:“共同配送是指由多个企业联合组织实施的配送活动。”
A.
正确
B.
错误
【单选题】I don't know ________. ________, I will tell you. [     ]
A.
if he comes;  If he comes
B.
if he will come;  If he will come
C.
if he comes;  If he will come
D.
if he will come;  If he comes
【简答题】If he makes an appointment, he can see the director. If he made an appointment, he _____ the director. If he had made an appointment, he _____ the director.
【简答题】ICMP是Internet控制协议报文协议,它允许主机或路由器报告 ______ 和提供有关异常情况的报告。它是 ______ 的组成部分,其报文格式包括报文头和数据区两部分,其中报文头部分是由 ______ 等三个字段组成,每个字段长度分别为 ______ 。ICMP可作为询问报文,用来测试目的站是否可达以及了解其有关状态。常用 ______ 命令来进行这种测试。
【单选题】Internet控制报文协议ICMP允许路由器报告差错情况和提供有关异常情况的报告,它的英文全称是( )。
A.
Internet Control Messag Protocol
B.
Internet Control Message Protocol
C.
Internet Contract Message Protocol
D.
Internet Control Message Prototype
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