Question

A bite from a tsetse fly (采采蝇) is an extremely unpleasant experience. It is not like a mosquito, which can put its thin mouthpart directly into your blood, often without you noticing. In contrast, the tsetse fly’s mouth has tiny saws on it that saw into your skin on its way to suck out your blood.

To make matters worse, several species of tsetse fly can transmit diseases. One of the most dangerous is a parasite that causes ＂sleeping sickness＂, or ＂human African trypanosomiasis＂to give it its official name. Without treatment, an infection is usually fatal.

Like so many tropical diseases, sleeping sickness has often been neglected by medical researchers. However, researchers have long endeavored to understand how it avoids our bodies’ defence mechanisms. Some of their insights could now help us eliminate sleeping sickness altogether.

There are two closely-related single-celled parasites that cause this deathly sleep: Trypanosoma brucei rhodesiense and T. b. gambiense. The latter is far more common: it is responsible for up to 95% of cases, mostly in western Africa. It takes several years to kill a person, while T. brucei rhodesiense can cause death within months. There are still other forms that infect livestock.

After the initial bite, sleeping sickness symptoms often start with a fever, headaches and aching muscles. As the illness goes on, those infected become increasingly tired, which is where it gets its name. Personality changes, severe confusion and poor coordination can also happen.

While medication does help, some treatments are toxic and can themselves be deadly, especially if they are given after the disease has reached the brain.

It is worth noting that sleeping sickness is no longer as deadly as it once was. In the early 20th Century several hundred thousand people were infected each year. By the 1960s the disease was considered ＂under control＂ and had reached very low numbers, making its spread more difficult. But in the 1970s there was another major epidemic, which took 20 years to control.

Since then, better screening programmes and earlier interventions have reduced the number of cases dramatically. In 2009 there were fewer than 10,000 cases for the first time since records began, and in 2015 this figure dropped to fewer than 3,000, according to the latest figures from the World Health Organisation. The WHO hopes the disease will be completely eliminated by 2020.

While this decline looks positive, there may be many more cases that go unreported in rural Africa. To eliminate the disease completely, infections have to be closely monitored.

More problematically, a series of new studies have shown that the parasite is more complicated than previously believed.

Sleeping sickness has always been considered —— and diagnosed —— as a blood disease, because T. brucei parasites can readily be detected in the blood of its victims.

1.A tsetse fly is different from a mosquito in that________.

A. it can put its thin mouthpart directly into your blood

B. all species of tsetse fly can transmit diseases

C. it can spread a parasite that causes ＂sleeping sickness＂

D. its mouth has larger saws than those on a mosquito

2.What can be learned about ＂sleeping sickness＂ according to the text ?

A. It is formally called＂human American trypanosomiasis＂.

B. If left untreated, it can possibly be deadly.

C. It remains as deadly as it used to be.

D. It usually draws attention from medical researchers.

3.What is implied in the last three paragraphs ?

A. ＂Sleeping sickness＂ will be completely eliminated by 2020.

B. The parasite causing ＂sleeping sickness＂ is easy to detect now.

C. T. brucei parasites can only be detected in the blood of its victims.

D. Data about ＂sleeping sickness＂cases may not be so accurate.

4.What would be the best title of this passage ?

A. A mosquito that can carry deadly diseases.

B. A bite from this fly puts you into a deadly sleep.

C. Symptoms that are characteristic of ＂sleeping sickness＂.

D. How to control deadly＂sleeping sickness＂ from a tsetse fly.

Answer

1.C

2.B

3.D

4.B

【解析】本篇为说明文。介绍了一种叫采采蝇的昆虫，可以传播疾病。这种病叫＂昏睡病＂，这种病随着进展会让患者越来越疲倦，如果不治的话可能会使人丧命。尽管目前人们已逐渐掌握它的特点，但也不可忽视。

1.细节理解题。根据文章第一段中“It is not like a mosquito, which can put its thin mouthpart directly into your blood, ”可知，它可以把它的薄薄的嘴直接塞进你的血液里的是mosquito，而不是tsetse fly，因此A项错误；根据文章第二段首句＂To make matters worse, several species of tsetse fly can transmit diseases＂可知，采采蝇的several species 会传播疾病，而不是 all species，因此B项错误；根据文章第一段中＂the tsetse fly’s mouth has tiny saws＂可知，采采蝇的嘴巴有tiny saws，而不是larger saws，因此D项错误；根据文章第二段＂several species of tsetse fly can transmit diseases. One of the most dangerous is a parasite that causes ‘sleeping sickness’,＂可知，采采蝇可以传播一种寄生虫，导致“昏睡病”因此C项正确。

2.推理判断题。根据文章第二段中“One of the most dangerous is a parasite that causes ‘sleeping sickness’, or ‘human African trypanosomiasis’ to give it its official name. ”可知，sleeping sickness的学名是human African trypanosomiasis，而不是human American trypanosomiasis，因此A项错误；根据文章第七段首句＂sleeping sickness is no longer as deadly as it once was.＂可知，现在昏睡病已经不像过去那样致命了，因此C项错误；根据文章第三段首句＂ sleeping sickness has often been neglected by medical researchers. ＂可知，昏睡病常常被医学研究者忽视，因此D项错误；根据文章第二段最后一句＂Without treatment, an infection is usually fatal.＂可知，如果不加以治疗，它可能是致命的，因此B项正确。

3.推理判断题。根据文章第八段最后一句“The WHO hopes the disease will be completely eliminated by 2020.”可知，世卫组织希望到2020年完全消灭这种疾病，只是希望，并非确定2020年可以完全消灭，因此A项错误；根据文章倒数第二段“a series of new studies have shown that the parasite is more complicated than previously believed.”可知，一系列新的研究表明，寄生虫比以前认为的要复杂得多，文章中并未提及引起昏睡病的寄生虫现在很容易被发现，因此B项错误；根据文章最后一段＂T. brucei parasites can readily be detected in the blood of its victims＂可知，T. brucei 寄生虫很容易在受害者的血液中被检测到，而不是只能在受害者的血液中检测到，因此C项错误；根据文章倒数第三段中的＂While this decline looks positive, there may be many more cases that go unreported in rural Africa.＂可知，非洲农村可能还有更多的病例未报告，因此关于“昏睡病”病例的数据可能不那么准确，故D项正确。

由可以推出答案。

4.标题归纳题。整篇文章介绍了采采蝇，尤其说明它可以传播一种＂昏睡病＂，这种病会让患者丧命，因此B项正确。