集合M={3,2a},N={a,b},a,b为实数,若M∩N={2}则M∪N=(

题型:选择题

问题:

集合M={3,2a},N={a,b},a,b为实数,若M∩N={2}则M∪N=(  )

A.{0,1,2}

B.{0,1,3}

C.{0,2,3}

D.{1,2,3}

考点:集合间交、并、补的运算(用Venn图表示)
题型:选择题

If you’ve tried studying when you’re tired, you know that it can seem very impossible to do well.

A study of sleep in sparrows suggests the relationship between sleep and the ability to learn may be more complicated(复杂) than people knew.

Niels C·Rattenborg, a scientist from Wisconsin-Madison, wanted to find out how the sparrows were able to deal with getting so much less sleep. He and his team brought eight wild birds into a lab and watched them for one year. They invented a game to check how well the birds could learn. In the game, the sparrows had to peck(啄)three buttons (按钮)in a right order to get a food treat. The scientists discovered that the birds’  ability to learn the right button order depended on(依靠)two things: the time of year and the amount of sleep the birds had had.

During the migration(迁徙)season, the sparrows were restless at night and got much less sleep than usual. Even so, they were able to understand how to get the food quickly as if they’d had a regular night of sleep. Outside the migration season, they found the sparrows that got less sleep than usual had much more difficulty learning how to get the food treats than birds that had a regular sleep.

The results show that the sparrows can deal with much less sleep during the migration season than usual. If scientists can find out why, they may learn from sparrows and find ways of helping people deal with getting much less sleep. Until scientists fully understand the relationship between sleep and learning, it’s better to get plenty of sleep when preparing for an exam.

小题1:The passage is mainly about          .

A.sparrows’ migration.

B.sleep lessons from Sparrows.

C.how to get less sleep while studying

D.how sparrows that got less sleep get food treats小题2:Why can sparrows get much less sleep during the migration season?

A.They eat more.

B.The climate is better

C.They can get food quickly

D.Scientists still don’t know the reason.小题3:What fact does the passage lead you to believe?

A.We should sleep as little as sparrows do.

B.We should get enough sleep before an exam.

C.When tired, we should try to focus on(聚焦) our study.

D.When tired, we should check how we can sleep less than usual.

题型:选择题

卷积运算有两种效应,一种是展宽,还有一种就是被卷函数经过卷积运算,其细微结构在一定程度上被消除,函数本身的起伏振荡变得平缓圆滑,这种效应是()

A、锐化

B、平滑化

C、其它

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男性,30岁,酒后驾车发生车祸,右上腹受伤致肝破裂。神志清楚,上腹部明显压痛,面色苍白,四肢湿冷,脉搏130次/分,血压10.7/8kPa(80/60mmHg),尿少,口渴,过度换气。

采取下列监测措施中,哪一项是不必要的()。

A.肢体温度、皮色

B.精神状态

C.毛细血管充盈时间

D.头部CT检查

E.血压、脉搏、尿量

题型:选择题

"无恒德者,不可以作医,人命死生之系",出自的著作是()

A.《本草纲目》

B.《省心录·论医》

C.《迈蒙尼提斯祷文》

D.《外科正宗》

E.《备急千金要方》

题型:选择题

GB/T18857《配电线路带电作业技术导则》对带电作业人员应具备条件提出了具体要求,主要有哪些?

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