阅读理解。
Handshaking, though a European practice, is now often seen in big cities of China. Nobody knows exactly
when the practice started in Europe. It is said that long long ago in Europe when people met, they showed their
unarmed (无武器的) hands to each other as a sign of goodwill. As time went on and trade in cities grew
rapidly, people in cities began to clap each other' s hands to make a deal or to reach an agreement. This practice was later changed into shaking hands among friends on meeting or leaving each other."Let' s shake (hands) on
it" sometimes means agreement reached.
Do the Europeans shake hands wherever they go and with whomever they meet? No. Sometimes the
Chinese abroad reach out their hands too often to be polite. It is really very impolite to give your hand when the
other party, especially when it is a woman, shows little interest in shaking hands with you and when the meeting does not mean anything to him or her. Even if, for politeness, he holds out his unwilling hand in answer to your uninvited hand, just touch it slightly. There is generally a misunderstanding (误解) among the Chinese that
westerners are usually open and straightforward, while the Chinese are rather reserved (保守的) in manner. But
in fact some people in western countries are more reserved than some Chinese today. So it is a good idea to
shake hands with a westerner only when he shows interest in further relations with you.
1. In the old days in Europe, people put out their unarmed hands to each other ______.
A. to make a deal
B. to greet each other
C. to show friendliness
D. to reach an agreement
2. The first paragraph mainly tells us _______.
A. where handshaking was first practiced
B. how handshaking came about
C. about the relationship between handshaking and trade
D. about the practice of handshaking both in Europe and in China
3. According to the text, which of the following statements is true?
A. Westerners are more reserved than the Chinese.
B. Westerners are unwilling to shake hands.
C. We should make a judgment before shaking hands.
D. We shouldn't' t shake hands with European women.
4. The main purpose of the text is______.
A. to tell us some differences between the East and the West
B. to offer us some important facts about handshaking
C. to introduce us to some different customs in the West
D. to give us some advice before we travel abroad
，再对其中一个物体m受力分析如图所示，受到的摩擦力
，即木块与挡板间摩擦力大小与两板间距离无关，所以B正确，A错误；由图可得
，由于挡板距离增大θ随之增大，故FN增大，所以C正确D错误．