题目内容：

Researchers are finding new ways to save snakebite victims.Experts discussed the latest findings during a recent conference.

Scientists in Australia have shown that a chemical called nitric oxide could increase the chances of surviving a poisonous snakebite.The scientists injected rats with a deadly amount of snake venom.Then they rubbed an ointment(软膏)containing nitric oxide on the skin around the injection site.The study found that the rats lived about one-third longer than if nitric oxide had not been used.But the treatment had to be started very quickly.

Dirk van Helden led the research.He says the nitric oxide ointment also showed promise in humans.The study appeared earlier this year in the journal Nature Medicine.Scientists say the findings could help save many lives.A recent study found that poisonous snakes cause as many as ninety-four thousand deaths worldwide each year.But Ulrich Kuch of the Biodiversity and Climate Research Center in Frankfurt,Germany,says that number appears to be low.

Mr Kuch says many deaths could be prohibited if snakebite victims are treated correctly,but they often go to traditional healers or do not seek any help at all.He said,“Sometimes it’s because there is no treatment available—no antivenom(抗蛇毒血清),which is the specific(特殊的)drug to treat snakebites—or health care staff do not know how to treat snakebites,and sometimes it’s because transportation to get to a health facility is not available or too expensive.”

Here is no single antivenom that can be used to treat all snakebites.The antivenom must be specific to the kind of snake that bit the person.In some countries the treatment is costly,while in others there is no such treatment.

1.What is this passage mainly about?(  )

A.Snakebite deaths around the world.

B.Progress in fighting snakebite deaths.

C.Snakebite treatment around the world.

D.The chances of surviving a poisonous snakebite.

2.After being rubbed an ointment containing nitric oxide,the rats    .

A.suffered no pain          B.died immediately

C.lived a little longer    D.started feeling uncomfortable

3.What does Paragraph 3 suggest?(  )

A.The number of deaths caused by snakebites is becoming lower each year.

B.The nitric oxide ointment has saved thousands of people’s lives.

C.It is very important to find an effective way to treat snakebites.

D.The number of deaths caused by snakebites worldwide is low.

4.What does the underlined word “prohibited” in Paragraph 4 mean?(  )

A. caused.    B.considered.

C.examined.     D.prevented.

5.What is implied in the last paragraph?(  )

A.Antivenom can be made very easily.

B.It’s very important to use the correct antivenom to treat snakebite victims.

C.Antivenom is extremely expensive all over the world.

D.A person bitten by a snake will survive as long as there is antivenom.