People have different ways of dealing with a common cold.Some take over-the-counter medicines such as aspirin （阿司匹林） while others try popular home remedies （疗法） like herbal tea or chicken soup.
  Yet here is the tough truth about the common cold：nothing really cures it.
  So why do people sometimes believe that their remedies work？ According to James Taylor,professor at the University of Washington,colds usually go away on their own in about a week,improving a little each day after symptoms peak,so it's easy to believe that it's medicine-rather than time -that deserves the credit（赞誉），USA Today reported.
  It still seems hard to believe that we can tackle much more serious diseases yet are powerless against something so common as a cold.Recently, scientists came closer to figuring out why.
  To understand it, you first need to know how antiviral （抗病毒的） drugs work.They attack the virus by attaching to and changing the surface structures（结构） of the virus.To do that, the drug must fit and lock into the virus like the right piece of a jigsaw （拼图） puzzle, which means scientists have to identify the virus and build a 3-D model to study its surface before they can design an antiviral drug that is effective enough.
  The two cold viruses that scientists had long known about were rhinovirus A and B. But they didn't find out about the existence of a third virus, rhinovirus C， until 2006. All three of them contribute to the common cold, but drugs that work well against rhinovirus A and B have little effect when used against C.
  "This explains most of the previous failures of drug trials against rhinovirus," study leader Professor Ann Palmenberg at University of Wisconsin-Madison, US， told Science Daily.
  Now, more than 10 years after the discovery of rhinovirus C， scientists have finally built a highly-detailed（高清的） 3-D model of the virus, showing that the surface of the virus is, as expected, different from that of other cold viruses.
  With the model in hand, hopefully a real cure for common cold is on its way. Soon, we may no longer have to waste our money on medicines that don't really work.



The author thinks traditional home remedies the common cold ______ .

A. are effective against
B. actually have no effect on
C. are slightly helpful in fighting
D. still need to be improved to work on

We can learn from the article that today's antiviral drugs work mainly by ______ .

A. absorbing different kinds of cold viruses at the same time
B. preventing colds from developing into serious diseases
C. changing the surface structures of known cold viruses
D. breaking up cold viruses directly

We can infer from the article that ______ .

A. scientists have already found a cure for the common cold
B. the surface of cold viruses looks quite similar
C. scientists were unaware of the existence of rhinovirus C until recently
D. understanding the structure of cold viruses is the key to developing an effective cure

What does the article mainly talk about？ ______

A. Why current cold remedies are useless.
B. How drug trials helped scientists find cures for the common cold.
C. How scientists found a previously unknown cold virus.
D. Why the new 3-D model of the cold virus is significant.