Dr. Jack M. Gwaltney, Jr. a professor at the University Of Virginia School Of Medicine infected six student volunteers with virus, the most common cause of colds. A few days later, when they were coughing and sneezing, he gathered 37 more people and divided them into three groups. Group 1 members spent three days and nights in the same room with one of the infected students, separated by a screen so they couldn't touch one another. Group 2 sat around a table while an infected volunteer talked, coughed and sang to them. Group 3 held hands with an infected student for ten seconds, and then touched their own noses or eyes.
Although most scientists at the time, the mid-70s, believed colds were spread by virus-laden droplets spread through the air when infected people coughed or sneezed, Gwaltney suspected physical contact might play an important role. Sure enough, of the 15 people who had touched a student volunteer, 11 became infected—compared with only one of those who had been sitting at the table, and none who had spent three days and nights together.
"The best evidence we have is that hand-to-hand contact is the most efficient way of transmitting virus," says Gwaltney. The study was one of a series that helped establish Gwaltney's reputation as a leading authority. Dr. Robert Couch says, "It would not be inappropriate to call him Mr. Common Cold."
When Gwaltney is asked how close scientists are to finding a cure, he replies: "If you mean ‘get rid of’, I don't think we're going to be able to do that with cold viruses any time soon. But if you look in the dictionary, you'll see that 'cure' is explained as a successful treatment. And we're not just getting more effective at treating the symptoms (症状)—we're getting at the root cause too. "
Dr. Jack M. Gwaltney conducted the experiment in order to__________.

A．find out the most common cause of colds

B．infect the student volunteer

C．find out the role physical contact plays in the common colds

D．find out the role virus-laden air plays in the infection of colds

The result of the experiment shows that ___ plays an important role in the infection of colds.

A．sneezing at the infected person

B．touching the infected person

C．sitting together with the infected person

D．talking with the infected person

Which of the following statements is TRUE according to the passage?

A．Dr. Gwaltney was sure that hand-to-hand touch is the cause of the common cold.

B．Only one of the people who had spent three days and nights together became infected.

C．Dr. Gwaltney conducted many an experiment as to the cause of colds.

D．Dr. Gwaltney tested altogether 43 volunteers to see how they could develop colds.

Mr. Common Cold is______.

A．a newly-found virus

B．a nickname (绰号) of respect to Dr. Gwaltney

C．a method to cure colds

D．a way by which the other scientists laughed at Dr. Gwaltney

When Dr. Gwaltney gives a reply in the end of the passage, he means that______.

A．they have found the fundamental cause of colds

B．they have managed to wipe out the cold viruses

C．they have meant to experiment more

D．they have made much progress in dealing with colds