问题 不定项选择

如图甲所示,理想变压器原、副线圈的匝数比为10:1,b是原线圈的中心抽头,图中电表均为理想的交流电表,定值电阻R=10 Ω,其余电阻均不计,从某时刻开始在原线圈c,d两端加上如图乙所示的交变电压.则下列说法中正确的是

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A.当单刀双掷开关与a连接时,电压表的示数为22 V

B.当单刀双掷开关与a连接且t=0.01 s时,电流表示数为零

C.当单刀双掷开关由a拨向b时,原线圈的输入功率变大

D.当单刀双掷开关由a拨向b时,副线圈输出电压的频率变为25 Hz

答案

AC

单项选择题

In its everyday life, Italy is very much the man’s world. However, because of the Italian’s understanding of foreigners, the woman tourist is able to invade many of the male places that are prohibited to Italian women. These places include the cafè and the wine shop.

In the large cities the cafè is a combination of club and office. Here, for the price of a coffee, an Italian can read all the newspapers brought to him. And he can transact business, with the waiter producing pen, ink, and stamps as needed. Or if he wants, he can sit outside under a canvas covering before the door and enjoy the sight of beautiful women passing by.

The wine shop, as a rule, is a more vigorous place than the caf6, and is filled almost exclusively with men. Wandering singers, generally in groups of two or three, add to the noise of these places with their songs and music. Many of the songs are of a political character and make fun of the leading statesmen of Italy, America, England, France, and Russia. But the songs are generally showing off a spirit of mischief. And when the criticism is about America, the American tourists find themselves laughing as much as anyone else. The Italian is a master at making fun of you and making you like it.

The Italian men are deep-rooted gamblers. They have been brought up to it as children, but they are cautious gamblers and never go too much in it. The national lottery used to be one of the most popular forms of gambling. But later a football stake had taken away much of the interest in the lottery. But here the important thing is that gambling, the same as drinking, seldom goes to an Italian’s head and his bets are not really dangerous risks. Even at cards the Italian plays for low stakes, generally for a cup of coffee or wine.

In this world of the Italian male it would be careless if the romanticism of the Italian were neglected. The Italian might well be described as the world’s greatest romanticist. From any boat in Venice to any member of the government in Rome, the Italian is always aware of romance, of love and of the importance of being a good lover.

on the beaches of Italy, the visitor is aware that the Italian really live for romance. His manners, his compliments, his charm and his general way of behaving are those of a romanticist. Almost every Italian you meet is convinced that he is another Casanova.

Romance is as much a part of Italy as its art and its history. Perhaps the feeling of romance that wells up in you when you come to Italy is one of the greatest things that Italy has to offer a world that is tired of war and political intrigue. It is the ideal place for a honeymoon because hotel managers and waiters make you conscious of your own love and stress it in such a way that you feel more in love in this country than in any other.

Many of the songs in the wine shop make fun of the leading statesmen in some countries because the singers want to ().

A.attract more political figures to the wine shop

B.criticize those leading statesmen

C.have fun and amuse the customers

D.arouse the leading statesmen’s attention

单项选择题 B1型题