问题 单项选择题

某压缩制冷装置的制冷剂在原冷凝器中因冷却介质改变,比原冷凝压力下的饱和温度低了5度,则制冷循环()。

A.冷量增加,功耗不变

B.冷量不变,功耗减少

C.冷量减少,功耗减小

D.冷量增加,功耗增加

答案

参考答案:C

阅读理解

阅读理解。

     "Tipping" (小费) is always a difficult business. You do not want to give too much or too little, or tip

the wrong person.

     In the UK and the USA, people usually tip waiters in restaurants, porters, taxi drivers and hairdressers.

They do not tip people in offices, cinemas, garages or airports.

     Do you invite your friend to the restaurant? Then you pay the bill. Does your friend invite you? Your

friend pays. If there are men and women in the party, the men usually pay.

     These days, men and women are equal (平等) in many ways. If you work in Britain or America, your

boss could be a man or a woman. There are increasing numbers (增长数据) of women in important

positions in politics (政治), law, medicine and in the business world.

     But it is still polite for a man to open doors for women and to ask them to go first. And it is polite for

men to stand up when they are introduced to women. On informal occasions (非正式场合), of course,

everyone is more relaxed.

1. In his passage, the writer tells us           . [ ]

A. not to give any tip to others

B. only to give up to women

C. only to give tip to old men

D. to give tip to the right person

2. If you invite your friends to a restaurant,           .[ ]

A. you should pay the bill

B. your friends should pay the bill

C. the person who orders the meal should pay the bill

D. you should ask your friends to pay the bill

3. Today in Britain and America           . [ ]

A. women are quite equal to men

B. men hold all the important positions in politics

C. women hold all the important positions in business

D. women have changed their conditions in many ways

4. It is polite for a man to           . [ ]

A. sit beside women

B. let women go first

C. stand beside a lady

D. drink for a lady

5. Which is impolite? [ ]

A. To open doors for women.

B. To ask women to go first.

C. To stand up when men are introduced to women.

D. To ask women to pay for a party.

阅读理解与欣赏

阅读《“脑疲劳”是怎么回事》,回答下列题。   

“脑疲劳”是怎么回事

  ①“脑疲劳”这种说法虽然比较新鲜,但这种现象早已有之。“脑疲劳”是一种“亚健康”状态,患者尤以脑力劳动者和在校学生为多。据专家调查分析,我国青少年群体当中,大约有 50%的人存在着不同程度的“脑疲劳”。令人忧虑的是,这种现象还有逐步蔓延的趋势。许多家长与教师不明白这个道理,还误以为孩子不求上进。殊不知患有“脑疲劳”的孩子能维持原有的状态已属不易。一般来说,“脑疲劳”通常表现为心理紧张、精神不振、思维紊乱、情绪波动、反应迟钝、记忆衰退、注意力分散和头晕头痛等。一旦出现“脑疲劳”,必须及时调整与治疗。否则,任其发展,轻则降低学习、工作的效率,影响生活质量,重则危及健康,引发多种身心疾病,甚至遗憾终生。那么,“脑疲劳”现象究竟是如何产生的呢?     

  ②从“身”的角度来看,有两个原因:一是用脑过度,导致物极必反,久而久之,大脑“疲劳” 容易,而“恢复”却十分缓慢;二是护体不当,五脏六腑、四肢百骸的毛病严重影响了脑功能的正常发挥,比如颈部气血不畅,便会造成营养物质向脑部输送困难。     

  ③从“心”的角度来看,也有两个原因:一是社会竞争日趋激烈,知识经济时代更强调既拼体力又拼脑力;二是家庭、学校、个人面对严峻升学与谋职形势,被迫人为地加大了大脑的工作强度。消耗过大而摄养不足,自然会导致脑疲劳。     

  ④伴随着科技的猛烈发展,人类已进入揭示生命奥秘的历史阶段。就人类“脑功能”而言,至少有两大课题亟待研究:一是如何避免或消除“脑疲劳”或“脑萎缩”(近年来已呈现出明显的低龄化趋势);二是如何最大限度地开发大脑潜力,更好地造福于社会人群。现代青年学生自强、勤奋、好学是应该给予肯定的,但必须采取科学的策略和方法。否则,不仅违背善良的初衷反而会导致大脑长期超负荷运转诱发典型的“脑疲劳”现象。在这方面教训是十分深刻的。不过如果你发现自己已经出现了轻微的“脑疲劳”现象也不必过分紧张。应该放松身心,学会科学用脑,做到劳逸适度,让大脑保持最佳状态。同时,还要注意饮食与睡眠,也可以适量地做一些脑部运动。     

  ⑤只要方法科学,持之以恒,消除大脑疾患,挖掘大脑潜能,就决不是镜花水月的痴心梦想。但愿每一位青年朋友都能通过自身的不懈努力,最终战胜“脑疲劳”,进而追求“脑轻松”的理想境界!

1.细读全文,概括本文说明的主要内容。

________________________________。

2.第④段加粗体的“善良的初衷”指代什么?

________________________________。

3.指出下面句子所使用的说明方法。

  据专家调查分析,我国青少年群体当中,大约有50%的人存在着不同程度的“脑疲劳”。

_______________________________。

4.结合本文内容与生活实际,提出几条消除大脑疲劳、发掘大脑潜能的建议。

_______________________________。