下列产品组中,哪一组产品的交叉价格弹性为负值()。 A.汽车和轮胎 B.花生油和豆油

题型:单项选择题

问题:

下列产品组中,哪一组产品的交叉价格弹性为负值()。

A.汽车和轮胎

B.花生油和豆油

C.棉布和化纤布

D.大米和面粉

考点:管理经济学管理经济学题库
题型:单项选择题

阅读理解。

     Now, China has the second largest number of Internet users in the world after the United States.

Many of Chinese Internet users are teenagers. They spend about 13 hours every week online. On the

Internet, students can find out almost anything. Surfing the Internet(网上冲浪)can help them with their

homework and learn a lot of knowledge.

     People can use the Internet to write letters, stories and to send emails. Many teenagers keep in touch with their friends online. They can also make new friends through QQ or ICQ.

     Some of the students surf the Internet just for fun. They like to listen to music, watch films, and go to

their favourite stars' websites.

     But some parents always think that the Internet takes young people away from study. "They spend

too much time playing computer games and most games are about killing and fighting. It's too dangerous.

And there are some dirty things on the Internet, "says the mother of a 13-year-old boy.

1. According to this passage, China has the ______ highest number of Internet users.

A. second

B. third

C. fourth

D. fifth

2. The phrase"keep in touch with"means ______ .

A. 浏览网站

B. 交朋友

C. 打电话

D. 保持联系

3. Some of the students surf the Internet for fun. What can they do?

A. They can listen to music and watch films.

B. They can go to their favourite stars' websites.

C. A and B.

D. We don't know.

4. Some parents worry that the Internet is ______ .

A. helpful

B. dangerous

C. traditional

D. useful

5. What's the best title of this article?

A. The Internet

B. The Computer

C. The Teenagers

D. Surfing the Internet

题型:单项选择题

适合保存种子延长种子寿命的环境是[ ]

A.低温、干燥    

B.高温、潮湿    

C.低温、潮湿    

D.高温、干燥

题型:单项选择题

可用作霍乱弧菌的运输保存的培养基是()

A.碱性蛋白胨水

B.P、V平板

C.SS琼脂

D.EC肉汤

E.GN增菌液

题型:单项选择题

患者女,30岁。继发不孕伴痛经2年。妇科检查:宫颈光滑,子宫后位,正常大小,粘连固定,经 * * 后穹扪及触痛结节。应诊断为()

A.卵巢癌

B.子宫内膜异位症

C.慢性盆腔炎

D.子宫腺肌病

E.盆腔淤血症

题型:单项选择题

以下哪一项是肾功能IV期的一般临床表现:()

A.肾脏已不能完全清除蛋白质代谢后的“垃圾”,病人感觉不到明显不适,但肾功能已有损害。

B.肾功能丢失达到80~90%,肾脏清除体内垃圾及排水的能力明显下降,毒素在体内蓄积,并产生中毒症状:无力、疲劳、食欲减退、恶心呕吐、失眠等

C.肾功能丢失达95%以上,肾功能基本丧失,毒素和水盐的蓄积可能威胁生命,需要采用透析或肾移植等替代治疗。

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