问题 单项选择题

雪卡毒素属于神经毒素,无色无味,脂溶性,不溶于水,耐热,不易被胃酸破坏,主要存在于热带珊瑚的内脏、肌肉中,尤以内脏中的含量最高。雪卡毒素主要影响人类的胃肠道和神经系统,雪卡毒素中毒的症状与有机磷中毒有些相似,一些受害者开始感到唇、舌和喉刺痛,接着在这些地方出现麻木,另一些病例首先的症状是恶心和呕吐,接着是口干、肠痉挛、腹泻、头痛、寒颤、发热和肌肉痛等症状,接触冷水犹如触电般刺痛,中毒持续恶化直到患者不能行走。中毒症状可持续几小时到几周,甚至数月,最严重者会导致死亡。 对上述文字概括最准确的是( )。

A.雪卡毒素属于神经毒素

B.雪卡毒素的存在

C.雪卡毒素中毒的症状

D.雪卡毒素的特性,存在和危害性

答案

参考答案:D

解析: 文段首先介绍了雪卡毒素的一些性状,接着介绍了雪卡毒素主要存在于热带珊瑚的内脏和肌肉中,又介绍了雪卡毒素的中毒症状及其危害性。所以对文段概括最准确的是D项。A、B、C项只描述了雪卡毒素的一个方面,是片面的。

阅读理解

阅读理解。

     An Australian man who has been donating his extremely rare kind of blood for 56 years has saved the

lives of more than two million babies.

     James Harrison has an antibody in his plasma (血浆) that stops babies dying from Rhesus disease, a

form of severe anemia (贫血症). He has enabled countless mothers to give birth to healthy babies,

including his own daughter, Tracey, who had a healthy son thanks to her father's blood.

     Mr. Harrison has been giving blood every few weeks since he was 18 years old and has now added

up to a total of 984 donations. When he started donating, his blood was regarded so special that his life

was insured for one million Australian dollars.

     He was also nicknamed the "man with the golden arm" or the "man in two million". He said, "I've never

thought about stopping. Never." He made a promise to be a donor aged 14 after taking major chest

surgery in which he needed 13 liters of blood. "I was in hospital for three months," he said. "The blood I

received saved my life so I made a pledge to give blood when I was 18."

     Just after he started donating he was found to have the rare and life-saving antibody in his blood. At

the time, thousands of babies in Australia were dying each year of Rhesus disease. Other newborns

suffered permanent brain damage because of the condition. The disease creates an incompatibility

between the mother's blood and her unborn baby's blood. It stems from one having Rh-positive

blood and the other Rh-negative.

     His blood has since led to the development of a vaccine (疫苗) called Anti-D. After his blood type

was discovered, Mr. Harrison volunteered to have a series of tests to help develop the Anti-D vaccine.

"They insured me for a million dollars so I knew my wife Barbara would be taken care of," he said. "I

wasn't scared. I was glad to help. I had to sign every form going and basically sign my life away."

     Mr. Harrison is Rh-negative and was given injections of Rh-positive blood. It was found his plasma

could treat the condition and since then it has been given to hundreds of thousands of women. It has also

been given to babies after they are born to stop them developing the disease.

     It is estimated he has helped save 2.2 million babies so far. Mr. Harrison is still donating every few

weeks now.

1. How old is James Harrison?

A. 56  

B. 70 

C. 74  

D. 78

2. Why did James decide to donate his blood? Because           .

A. his daughter asked him to help her son

B. he has a golden arm worth a million dollars

C. a vaccine called Anti-D is to be developed

D. someone else's blood saved his life

3. The underlined sentence (in Paragraph 5) suggests that           .

A. babies suffer permanent brain damage before their birth

B. the mother and the baby have different types of blood

C. Rhesus disease contributes to permanent brain damage

D. all the patients have a rare antibody in their blood

4. What can we infer from the sixth paragraph?

A. Some of the tests to develop the vaccine are dangerous.

B. His wife Barbara needed to be taken care of badly then.

C. Mr. Harrison was glad to help develop a new vaccine.

D. His blood type was accidentally discovered after tests.

单项选择题