Passage two

Why do we cry? Can you imagine life without tears? Not only do tears keep
your eyes lubricated, they also contain a substance that kills certain
bacteria so they can't infect your eyes. Give up your tears ,and you'll
lose this on-the-spot defense. Nobody wants to give up the flood of extra
tears you produce when you get something physical or chemical in your
eyes. Tears are very good at washing this irritating stuff out .Another
thing you couldn't do without your tears is cry from joy, anger or
sadness. Humans are the only animals that produce tears in response to
emotions, and most people say a good cry makes them feel better. Many
scientists, therefore, believe that crying somehow helps us cope with
emotional situations. Tear researcher, Winifred, is trying to figure out
how it happens. One possibility he says is that tears discharge certain
chemicals from your body, chemicals that build up during stress. When
people talk about crying it out," I think that might actually be what they
are doing", he says. If Fred is right, what do you think will happen to
people who restrain their tears? Boys, for example, cry only about a
quarter as often as girls once they reach teenage years, and we all cry a
lot less now than we did as babies. Could it possibly be that we face less
stress? Maybe we found another ways to deal with it, or maybe we just feel
embarrassed.

Questions 14-17 are based on the passage you have just heard.
14.What's the topic discussed in this passage?
15.What is Winifred trying to find out?
16.What does the passage say about teenage boys and girls?
17.What's the difference between human beings and other animals when
shedding tears?