单选题An electronic depth finder operates on the principle that（）.A radio signals reflect from a solid surfaceB sound waves travel at a constant speed through waterC radar signals travel at a constant speed through waterD pressure increases with depth

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单选题

An electronic depth finder operates on the principle that（）.

radio signals reflect from a solid surface

sound waves travel at a constant speed through water

radar signals travel at a constant speed through water

pressure increases with depth

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相似问题和答案

第1题：

狭义的电子商务的英文表达是:()

A.Electronic Government

B.Electronic Business

C. Electronic Banking

D.Electronic Commerce

参考答案：D

第2题：

中文“电子商务”一词源于英文的“(25)”。

A．Electronic Consumer

B．Electronic Commerce

C．Electronic Change

D．Electronic Communication

正确答案：B
解析：本题考查电子商务的基本概念，电子商务源于英文Electronic　Commerce，简写为EC。

第3题：

() that store digital certificates are particularyly handy when you shop at a site that.

A、None of the above

B、Electronic checks

C、Electronic wallets

D、Electronic Cash

参考答案：C

第4题：

MIDI enables people to use （请作答此空）computers and electronic musical instruments. There are actually three components to MIDI, the communications"（）", the Hardware interface and a distribution（）called "Standard MIDI Files". In the context of the WWW, the most interesting component is the （）Format. In principle, MIDI files contain sequences of MIDI Protocol messages: However, when MIDI Protocol（）are stored in MIDI files, the events are also time-stamped for playback in the proper sequence. Music delivered by MIDI files is the most common use of MIDI today.

A.personal
B.electronic]
C.multimedia]
D.network

答案：C

解析：

MIDI使得人们能够使用多媒体计算机和电子乐器。实际上MIDI有3种元素：通信协议、硬件接口和被称为标准MIDI文件的发布格式。在WWW环境中，最重要的元素是音频格式。在原理上，MIDI文件包含了MIDI协议报文序列。然而当MIDI协议报文被存储在MIDI文件中时，事件都被加上了时间戳，以便于按照适当的顺序回放。由MIDI文件提供的音乐是MIDI当前最通常的应用。

第5题：

All echo-sounders can measure the ______．

A.Actual depth of water

B.Actual depth of water below keel

C.Average depth from waterline to hard bottom

D.Average depth of water to soft bottom

正确答案：B

第6题：

In the following statements about the principle of the low level controlling, which is WRONG? 0

A.Low level is monitored on the drain tank and header tank.

B.If there is high differential the filters pressure across the circulating

pumps is alarmed

C.The lubricating oil purifier cannot take oil from the drain tank

D.If the sea water pressure falls, this also operates an alarm

答案：C

第7题：

The height of tide is the ______.

A.depth of water at a specific time due to tidal effect

B.difference between the depth of the water and the area's tidal datum

C.difference between the depth of the water and the high water tidal level

D.difference between the depth of the water at high tide and the depth of the water at low tide

正确答案：B

第8题：

在系统预设的状态下,当在Finder窗口中双击其中一个文件夹图标时,将会()。

A.在原Finder窗口中打开并显示该文件夹内容

B.创建一个新的Finder窗口并显示该文件夹内容

C.在原Finder窗口中打开并显示“个人”目录内容

D.创建一个新的Finder窗口并显示“个人”目录内容

参考答案：A

第9题：

A channel is started as having a controlling depth of 38 feet. Which statement is TRUE?_____

A.At least 80% of the channel is cleared to the charted depth.

B.At least 50% of the channel is cleared to the charted depth.

C.100% of the channel depth is clear to 38 feet.

D.The sides of the channel conform to at least 50% of the controlling depth.

正确答案：C
航道被标注为38英尺的限制水深，则水道百分之百都拥有38英尺的水深。

第10题：

An（），serving a function similar to a physical wallet, holds credit card numbers, electronic cash, owner identification, and owner contact information and provides that information at an electronic commerce site's checkout counter.
A.electronic wallet
B.electronic commerce
C.third party payment
D.Internet banking

答案：A

解析：

An electronic depth finder operates on the principle that（）.

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