牧羊人的煩惱

江西 丁黎明

主題語(yǔ)境：畜牧業(yè) 篇幅：294詞 建議用時(shí)：6分鐘

1Sheep farmers in Australia and New Zealand have a problem.Their animals are affected by worms（寄生蟲）which cause them to become extremely thin and can,in severe cases,kill them.

2Dr Paz of the University of Western Australia knew from past work that sheep with severe worm problems tended to have abnormal bacterial populations in their waste.This led him to wonder whether the worms in the intestines(腸)of resistant sheep were somehow hampering the worms'activities.He and his team therefore looked at a flock of 200 sheep at a farm in Western Australia and selected ten that had particularly high loads of worm eggs in their waste(1,940 per gram,on average)and ten that had low loads(410 per gram,on average).

3As they had imagined,the researchers did indeed find systematic differences between the two groups.These differences were particularly notable in the small intestine,where the worms live,with resistant sheep having richer and more diverse bacterial populations in this part of the intestines than vulnerable animals did.In particular,the team noticed that populations of bacteria were especially abundant in the resistant animals.

4It is,of course,possible that the worms are affecting the sheep's micro-organisms in the intestines,rather than the other way around.But Dr Paz thinks this is unlikely,because all of the sheep seem to have some worms.Rather,he suspects,genetically resistant sheep are providing an intestinal environment beneficial to bacteria which either produce chemical elements that drive away the worms or consume resources which the worms depend on.If that is correct,it opens up a third approach to worm control,which is to employ probiotics （益生菌）to shape the intestine micro-organism of flocks directly,rather than relying on selective breeding to do it.

Reading Check

Detail1.What effect might worms have on sheep farmers?

A.They may suffer a economic loss.

B.They may become too thin.

C.They may be killed by worms.

D.They have to raise more sheep.

Vocabulary2.What does the underlined word“hampering”in paragraph 2 mean?

A.Contributing to. B.Helping.

C.Preventing. D.Managing.

Detail3.What are the new findings of Dr Paz?

A.Bacteria particularly like to live in sheep's small intestine.

B.Healthier sheep have more diverse bacteria populations in their intestines.

C.Sheep in Western Australia have more worms than those in New Zealand.

D.Sheep with serious worm problems tend to have abnormal bacterial populations.

Language Study

Difficult sentence in the text

These differences were particularly notable in the small intestine,where the worms live,with resistant sheep having richer and more diverse bacterial populations in this part of the intestines than vulnerable animals did.這些差異在寄生蟲生活的小腸中尤其顯著，與易受感染的羊相比，對(duì)寄生蟲有抵抗力的羊在腸道的這部分擁有更豐富和更多樣化的細(xì)菌種群。

【點(diǎn)石成金】本句是一個(gè)主從復(fù)合句，where引導(dǎo)的是非限制性定語(yǔ)從句，另有with的復(fù)合結(jié)構(gòu)作狀語(yǔ)。