问题 问答题 简答题

等电位连接网络的基本形式有几种?适用于什么系统?

答案

参考答案:

有两种,即S星型结构和M型网形结构,通常S型等电位连接网络适用相对较小、限定于局部的系统,而且所有设施管线和电缆宜从ERP点连接应从ERP处附近进入该信息系统;M型等电位连接网络宜用于延伸较大的开环系统,而且在设备之间敷设许多线路和电缆,以及设施和电缆从若干处进入该信息系统;在复杂系统中,M型和S型等电位连接网络这两种形式的优点可组合在一起。

阅读理解

B

People have strange ideas about food. For example, the tomato is a kind of very delicious vegetable. It is one of useful plants that can be prepared in many ways. It has rich nutrition and vitamin in it. But in the 18th century, Americans never ate tomatoes. They grew them in their gardens because tomato plants are so pretty. But they thought the vegetable was poisonous (有毒的). They called tomatoes “poison apples.”

President Thomas Jefferson, however, knew that tomatoes were good to eat. He was a learned man. He had been to Paris, where he learned to love the taste of tomatoes. He grew many kinds of tomatoes in his garden. The President taught his cook a way for a cream of tomato soup. This beautiful pink soup was served at the President’s party. The guests thought the soup tasted really good. They never thought their president would serve his honored guests poison apples. Jefferson never spoke to his honored (忠实的) guests about the fact.

46. After you read the passage, which of the following do you think is true?

A. Americans never ate tomatoes after they began to plant them.

B. Americans didn’t eat tomatoes before 19th century.

C. Even now Americans don’t eat tomatoes.

D. In the 18th century Americans ate a lot of tomatoes.

47. The passage tells us that Jefferson was a President who learned to love the taste of tomatoes       .

A. while he was in Paris           B. when he was a little boy

C. because his parents told him so   D. from books

48. According to the text, _______ made the beautiful pink soup served at the President’s party?

A. the President himself        B. a French cook

C. the President’s cook         D. the President’s wife

49. From the passage we know all the honored guests invited by Jefferson were      .

A. people from other countries           B. from France

C. people of his own country             D. men only

50. According to the passage, which of the following is NOT true?

A. All of the guests knew the soup that was served at the President’s party was made of tomatoes.

B. All of the guests thought the soup which was prepared by the President’s cook was nice.

C. All of the guests thought the taste of the beautiful pink soup was nice.

D. None of the guests knew that their president would serve his honored guests poison apples.

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