问题 多选题

(多选题)如图所示,两块三角形的木板B、C竖直放在水平桌面上,它们的顶点连接在A处,底边向两边分开.一个锥体置于A处,放手之后,奇特的现象发生了,椎体自动地沿木板滚上了B、C板的高处,不计一切阻力.下列说法正确的是(  )

A.锥体在滚动过程中重心逐渐升高

B.锥体在滚动过程中重心逐渐降低

C.锥体在滚动过程中机械能逐渐增大

D.锥体在滚动过程中机械能保持不变

答案

椎体自动地沿木板滚上了B、C板的高处的过程中只有重力做功,椎体机械能守恒,重力势能转化为动能,而高度上升,所以重心逐渐降低,故BD正确,AC错误.

故选BD

单项选择题
阅读理解

It happened to me recently that I was telling someone how much I had enjoyed reading Barack Obama’s Dreams From My Father and how it had changed my views of the current US President. The person I was talking to agreed with me that it was, in his words, “a wonderfully written book.” However, he then proceeded to talk about Mr. Obama in a way that suggested he had no idea of his background at all. I sensed that I was talking to a book liar(说谎者).

And it seems that he is not the only one. Clearly two thirds of people have lied about reading a book which they haven’t. In The World Book Day survey, Dreams From My Father is at number 9. The survey lists top ten books, and various authors, which people have lied about reading. As I’m not one to lie too often, I’ll admit here and now that I haven’t read the entire ten books. But I am pleased to say that I have read the book at number one, George Orwell’s 1984. I think it’s absolutely outstanding.

Asked why they lied, the most common reason was to impress someone they were speaking to. This could be difficult if the conversation became more in-depth!

The World Book Day survey also has some other interesting information in it. It shows that many people lie about having read classical works by Jane Austen, the Bronte sisters, Charles Dickens and so on. But when asked which authors they actually enjoy, they named JK Rowling, Jilly Cooper, and Stephen King. Forty-one percent of people asked admitted they turned to the back of the book to read the end before finishing the story.

So which books have you lied about reading —if any — and which is your favorite?

小题1:The main reason why people lie about reading is to __________.         

A.make fun of the listener

B.impress the listener

C.please the listener

D.interest the listener小题2:The underlined word “proceeded” in the passage probably means“___________”.

A.wanted

B.happened

C.continued

D.stopped小题3:What is the best title for the passage?

A.Are You A Book Liar?

B.Readers Are All Liars

C.World Book Day

D.Dreams From My Father