Narrator Listen to a part of a lecture in a business class. What does the professor say about the length of handshaking?

[Professor] Good afternoon. In today’s class I’d like to talk about an everyday social activity. That is handshake. Think about how you greet someone for the first time in your own country, in your own culture. When you’re introduced to a stranger, do you shake hands with him or her?
[Student A] Yes, we do it often in our country.
[Professor] So, could you tell the class something about it?
[Student A] Well, ...it’s just...just shaking hands, nothing special.
[Professor] If you think that simply shaking hands is enough, though, then you’d better listen to what I have to say next. How are shake hands is almost as important as the act itself. How you shake hands tells the other person a 10t about you. It’s especially so of men!
Here’s what I mean. A limp or weak handshake by a man has the same meaning as no handshake at all. The message is: "I’m not very interested in you." Think about this, because I know that some of you may come from cultures that accept limp handshakes as normal. Here, even if you don’t intend to, you may send the wrong message.
Is the best way, then, to use all your muscles and crush -- and possibly hurt -- the other person’s hand? The message behind this kind of handshake is aggressiveness and a desire to compete. Unless you specifically want to communicate these feeling to the other person, you don’t have to shake hands with all your strength. One more type of male handshake that can send the wrong message is the half handshake. Here, only the front half of the fingers is offered to the other person’s hand. The message is that you have little confidence, that you’re shy. "I’m not a strong or courageous person." That’s what a half handshake says. Ok, do you have anything to say?
[Student B] Yes, I’ve never thought there are so many things underlying such a simple social activity. But how about the women? They also shake hands.
[professor] You are right. Let’s look now at how it is for women. Until recently, women in many countries felt no great need to shake hands during introductions. That’s changed as more and more women are working in business, government and academia. The way that women used to shake hands with men was to give only half the hand -- that is, the fingers only. This gave little impression or message, at least to men. Nowadays, women are having to learn again how to shake hands. Now, women are beginning to offer all of the hand -- the fingers and palm. The other person’s hand is held and shaken firmly but not too hard. This communicates to the other person more of a feeling of competence or strength than the old-fashioned way of doing it.
[Student B] How long should you shake hands? I mean, does the length of time have any significance?
[Professor] That’s fight: the length of time you shake hands also says something about you. If a man lets go of the other person’s hand too quickly, what kind of message do you think that sends? Releasing your hand quite soon indicates that you don’t want to get too involved or you’re not very interested in the other person. That goes for both women and men. However, it’s both more acceptable and more common for two men to shake hands for a longer time, even as long as six or seven seconds. The message in this case is "I like you" and generally indicates that the two men think they’ll get on well.
Narrator Now get ready to answer some questions. You may use your notes to help you answer.
12. What is the talk mainly about?
13. What does the professor say about a weak handshake for men?
14. What does the professor say about the half handshake for men?
15. According to the professor, what is the cause for women’s change in hand-shakes?
16. What does the professor say about the length of handshaking?
Narrator Listen again to a part of the conversation. Then answer the question.
[Professor] Think about this, because I know that some of you may come from cultures that accept limp handshakes as normal. Here, even if you don’t intend to, you may send the wrong message.
17. Why does the professor say thisΩ?