问题 问答题 简答题

似层状汞、锑矿床其特征?

答案

参考答案:

矿区内一般无岩浆岩出露。矿体产于薄-中厚层灰岩、白云岩中,矿体之上常常是页岩、泥灰岩、泥质白云岩等。矿体多为层状、似层状、透镜状,沿断续分布,以褶皱轴部或层间剥离处矿化最厚向两侧逐渐变薄而尖灭。在似层状矿体重有时还半生脉状矿体,围岩蚀变比较简单,以硅化和碳酸盐化为主。

阅读理解

    Feel tired lately?Has a doctor said he can’t find anything wrong with you?Perhaps he sends you to a hospital,but all the advanced equipment there shows there is nothing wrong with you.

Then,consider this:you might be in a state of sub-health(亚健康).

Sub-health,also called the third state or gray state,is explained as borderline state between health and disease.

According to the investigation by the National Organization,over 45 percent of sub-health people are middle-aged or elderly.The percentage is even higher among people who work in management positions as well as students around exam-week.

Symptoms(征兆)include a lack of energy,depression,slow reactions,insomnia(失眠),agitation, and poor memory.Other symptoms include shortness of breath,sweating and aching in the waist and legs.

The key to preventing and recovering from sub-health,according to some medical experts,is to form good living habits, alternate work and rest, exercise regularly,and take part in open air activities.

As for meals,people are advised to eat less salt and sugar.They should also eat more fresh vegetables,fruits,fish because they are rich in nutritional elements—vitamins and trace elements(微量元素)—that are important to the body.

Nutrition experts point out that it is not good to eat too much at one meal because it may cause unhealthy changes in the digestive tract(消化道).They also say that a balanced diet is very helpful in avoiding sub-health.

小题1:When you are in a state of sub-health,you should ________.

A.stay home and keep silent

B.go to a doctor and buy some medicine

C.not consider it very serious

D.find out the reasons and relax yourself小题2:Middle-aged people may be easy to get sub-health because ________.

A.they have used up their energy

B.they have lost their living hopes

C.they have more pressure in life and work

D.they have changed their way of life小题3:The key to preventing you from falling into a state of sub-health is to ________.

A.keep on working regularly

B.go to sleep a bit earlier

C.form good living habits

D.take medicine if necessary小题4:The underlined word “alternate” in this passage is closest in meaning to ________.

A.arrange by turns

B.cause to take place

C.make up for

D.keep away from

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