问题 单项选择题

规程JJG313-2010规定,测量用电流互感器在额定频率,额定功率因数及二次负荷为到()之间的任一数值时,其误差不得超过相应准确度级别所规定的误差限值。

A.25%;80%

B.25%;100%

C.20%;80%

D.20%;100%

答案

参考答案:B

阅读理解

阅读文章,完成文章后的问题。

                                                                  Travel by train

      Jack loves traveling by train. Whenever he feels like traveling, he'd first think about taking a trip on the

rail. That is because he never has to bother to book (订) tickets or collect them in advance (提前). Going to

the station and buying a ticket are what he has to do.

      Traveling by train is also very comfortable. Most of the trains are air-conditioned, warm in winter and

cool in summer. Jack usually chooses a non-smoking section, taking a seat by the window so he can enjoy

the outside views. If it is a night train, the experience can be exciting. He just sleeps the whole night and the

next day, he will be in a new city. By the way, he never has to worry about his meals. The train provides

food around the clock. 

      Traveling by train has another advantage to offer: you may run into some old friends or you can listen

to people talking about something of your interest. Last week when he was on a train, for instance, he ran

into a primary school classmate. They didn't expect that they could bump into each other that way. Their

talk brought back many things: the games they played, the jokes they made on their peers and the funny

things they had done.

1. 请用简短的话概括文中提到的乘火车的三个优点。

     ________________________________________

     ________________________________________

2. How would you like to go to school? Why?

    ________________________________________

单项选择题