在△ABC中,角A、B、C所对的边分别为a,b,c,若a2+c2-ac=b2,则

题型:选择题

问题:

在△ABC中,角A、B、C所对的边分别为a,b,c,若a2+c2-ac=b2,则角B的大小为(  )
A.
3
B.
π
4
C.
π
6
D.
π
3
考点:余弦定理
题型:选择题

For hundreds Of years, scientists have been trying to answer what things have an effect on people’s emotions (情感). How you feel is controlled by many things. Your emotions can be affected by your personality, by the actions of others and by events around you. Perhaps you don’t know your emotions can be influenced by the weather as well.

People often say they feel good when the sun is shining and sad when it is cloudy. In fact, sunlight makes us feel good. When sunlight hits our skins, our bodies produce a vitamin. Vitamins are natural chemicals (化学物质) which we all need to stay healthy. Sunlight helps our bodies produce vitamin D. Vitamin D helps our bodies make a special chemical. This special chemical affects our brains (大脑) and makes us feel happy. For example, there are long, dark winters of little sunlight in Sweden and Norway, so many people in these countries often feel sad. Without much sunlight, their bodies produce less vitamin D. Without enough vitamin D, their bodies make less of this special chemical which makes them feel good. To help the people in these countries feel better, special “sunrooms” with artificial (人造的) lights have been built. People can go there and get “sunlight” for an hour or two!

The weather can also affect people’s emotions in other ways. Hot weather can make people angry because people feel uncomfortable when they are hot. In the same way, rain can make people angry because being wet can be unpleasant. As you can see, the weather can have an effect on the chemicals which control our brains. Through these ways, the weather can influence our emotions. Sadly, while the weather can change us, we can hardly change the weather.

小题1: Which of the following is NOT mentioned as a factor (因素) that can affect one’s emotions?

A.Weather.

B.Actions of others.

C.Personality.

D.Age.小题2:Which of the following is true about vitamin D according to the passage?

A.It is a kind of artificial chemical.

B.It makes us worried by affecting our brains.

C.It is needed by us all to keep fit.

D.It is in the sunlight.小题3: What can we infer (推断) from the passage?

A.We feel good when we are in the bright cool weather.

B.We will be happy when we are caught in the rain.

C.All people in Norway and Sweden feel sad in winter.

D.The more vitamin D you have, the happier you’ll be.小题4:What may be the best title for this passage?

A.Why Do We Feel Sad?

B.The Weather Influences People’s Emotions

C.People Need More Vitamin D

D.We Can Hardly Change the Weather

题型:选择题

下列各项,不属于实证与虚证鉴别要点的是()。

A.病程的长短

B.体质虚弱与壮实

C.精神萎靡与兴奋

D.疼痛喜按与拒按

E.面色苍白或通红

题型:选择题

下列属大肠经穴的是()。

A.曲池

B.内关

C.三阴交

D.太渊

E.太冲

题型:选择题

根据领导行为四分图理论,对成熟的护士最适宜采取的领导方式是

A.高任务,高关心人

B.高任务,低关心人

C.低任务,高关心人

D.低任务,低关心人

E.不分配任务,高关心人

题型:选择题

各级人民政府对具有代表性的各种类型的自然生态系统区域,珍稀、濒危的野生动植物自然分布区域,重要的水源涵养区域,应当采取措施加以保护,严禁破坏。()

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