问题 单项选择题

肺内压的变化是()。

A.吸气时大于呼气时

B.吸气末大于呼气末

C.吸气时等于呼气时

D.吸气末等于呼气末

E.吸气时等于呼气末

答案

参考答案:D

解析:

肺内压是指气道和肺泡内气体的压力。肺通过呼吸道与外界相通,在呼吸暂停,呼吸通畅时,肺内压与大气压相等。在呼吸过程中气体之所以能进入肺泡,是肺泡与大气压之间存在着一些压力差,气体从压力高出流向压力低处。呼吸之初,由于肺随胸廓扩大而增大了容积,肺泡内原有气量未变,致使肺内压力下降低于大气压,空气即借此压力差通过呼吸道进入肺泡;到呼吸末期,进入的空气已充满了扩大的肺容积,故肺内压又与大气压相等。呼气初,肺容积小,气体被压缩,于是肺内压高于大气压,肺泡气体通过呼吸道流向外界,至呼气末期,肺内压又与大气压相等。

阅读理解

If you live in the United States, you can’t have a full-time job until you are 16 years old. At 14 or 15, you work part-time after school or on weekends, and during summer vacation you can work 40 hours each week. Does all that mean that if you are younger than 14, you can’t make your own money? Of course not! Kids from 10-13 years of age can make money by doing lots of things.

Valerie, 11, told us that she made money by cleaning up other people’s yards. Lena, 13, makes money by knitting(织) dog sweaters and selling them to her neighbors. Reisa said she had started taking art classes and showing her works to people. People ask her to draw pictures for them and they pay her for them. Jasmine. 13, writes articles for different magazines!

Kids can learn lots of things from making money. By working to make your own money, you are learning the skills you will need in life. These skills can include things like how to get along with others, how to use technology and how to use your time wisely. Some people think that asking for money is a lot easier than making it; however, if you can make your own money, you don’t have to depend on anyone else. The five dollars that you make will probably make you feel a lot better than the twenty dollars you ask for.

小题1: Kids can have full-time jobs at the age of______ in the USA.

A. 17        B.15           C. 14           D. 13

小题2: If you are 15 years old, you can’t work part-time______.

A.after school

B.on weekends

C.during school time

D.during summer vacation小题3: Riesa makes money by_______.

A.cleaning up other people’s yard

B.drawing pictures for others

C.writing articles for different magazines

D.knitting dog sweaters.小题4:According to the passage, which of the following is NOT true?

A.The writer thinks kids from 10-13 years of age can make money too.

B.Kids can learn how to use their time wisely by making money.

C.Kids don’t need to get along with others when making money.

D.Kids can learn skills if they try to make money on their own.

单项选择题