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问题 不定项选择

如图所示，某同学将空的薄金属筒开口向下压入水中。设水温均匀且恒定，筒内空气无泄漏，不计气体分子间的相互作用，则被淹没的金属筒在缓慢下降过程中，筒内空气体积减小

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A．从外界吸热

B．内能增大

C．向外界放热

D．内能减小

答案

答案：C

单项选择题

For each blank, choose the best answer from the four choices and write down on the answer sheet.
(11) is a protocol that a host uses to inform a router when it joins Or leaves an Internet multicast group.
(12) is an error detection code that most data communication networks use.
(13) is an interior gateway protocol that uses a distance vector algorithm to propagate routing information.
(14) is a transfer mode in which all types of information are organized into fixed form cells on an asynchronous or non-periodic basis over a range of media.
(15) is an identifier of a web page.

A．ISDN

B．X.25

C．Frame Relay

D．ATM
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单项选择题

基底细胞癌好发于

A．下唇

B．颊黏膜

C．颜面皮肤

D．额部

E．口角
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