问题 问答题 论述题

简述土壤的流行病学意义。

答案

参考答案:

土壤经常受生活废弃物的污染,大量的致病微生物和蠕虫卵由粪便带入土壤。

(1)致病微生物和寄生虫卵在土壤中有一定的存活力,因此土壤成为病原体的储存场所。

(2)进入土壤的病原体可通过直接接触传播,也可通过人、动物-土壤-水、农作物-人间接途径感染人体。

(3)土壤污染在流行病学上的危险性不仅取决于土壤对于病原体的负荷以及病原体的存活和繁殖情况,而且取决于个人和食品卫生水平、社会成员的生活习惯、微生物的毒力、宿主的营养和免疫状态等。

阅读理解

A

There were smiling children all the way. Charily they knew at what time the train passed their homes and they made it their business to stand along the railway, wave to complete strangers and cheer them up as they rushed towards Penang. Often whole families stood outside their homes and waved and smiled as if those on the trains were their favorite relatives. This is the simple village people of Malaysia. I was moved.

I had always traveled to Malaysia by plane or car, so this was the first time I was on a train. I did not particularly relish the long train journey and had brought along a dozen magazines to read and reread. I looked about the train. There was not one familiar face. I sighed and sat down to read my Economics.

It was not long before the train was across the Causeway and in Malaysia. Johore Baru was just another city like Singapore, so I was tired of looking at the crowds of people as they hurried past. As we went beyond the city, I watched the straight rows of rubber trees and miles and miles of green. Then the first village came into sight, Immediately I came alive; I decided to wave hack.

From then on my journey became interesting. I threw my magazines into the waste basket and decided to join in Malaysian life. Then everything came alive. The mountains seemed to speak to me. Even the trees were smiling. I stared at everything as if I was looking at it for the first time.

The day passed fast and I even forgot to have my lunch until I felt hungry. I looked at my watch and was surprised that it was 3:00 pm. Soon the train pulled up at Butterworth. I looked at the people all around me. They all looked beautiful. When my uncle arrived with a smile, I threw my arms around him to give him a warm hug (拥抱). I had never done this before. He seemed surprised and then his weather-beaten face warmed up with a huge smile. We walked arm in arm to his car. I looked forward to the return journey.

小题1:The author expected the train trip to be _______.

A.adventurous

B.pleasant

C.exciting

D.dull小题2:What did the author remember most fondly of her train trip?

A.The friendly country people.

B.The mountains along the way.

C.The crowds of people in the streets.

D.The simple lunch served on the train.小题3:Which of the following words can best take the place of the word“relish”in the second paragraph?

A.choose

B.enjoy

C.prepare for

D.carry on小题4:What can we learn from the story?

A.Comfort in traveling by train.

B.Pleasure of living in the country.

C.Reading gives people delight.

D.Smiles brighten people up.

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