2011年6月1日期，厦门市机关、学校和医院等室内场所全面禁烟，在空气不流通的房间里，只要有一个人吸烟，整个房间就会充满烟味．这是因为（ ）
A．物质是由分子组成的
B．分子在不停地运动
C．分子间有引力
D．分子间有斥力
一个人在房间吸烟，由于烟分子在不停地做无规则运动，在空气中进行扩散，所以整个房间充满烟味．所以只要有一个人吸烟，整个房间就会充满烟味的现象说明了分子在不停地运动，但并不能说明分子间存在引力和斥力，也不能说明物质是由分子组成的．
故选B．
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| A library is a place to find out about anything. In it there are mostly books, but there are also pictures, papers, maps, magazines and records. Special science and art shows, story hours, films, plays and contests may also be 1 in a library. Long ago a library had only books, and other things were 2 to get. There were so 3 books that no one was 4 to take them out of the library. After the printing machine was 5 , books could be made faster and librarians got more books. To borrow a book to 6 home today, a person just 7 a library card. The person goes to the main desk to have a librarian check the book out. The librarian prints the card with the 8 by which the book must be returned. If the book is returned 9 , the person must usually pay money for having broken the 10 . Books in a library are put in a certain 11 to help people to find 12 they want. In some libraries, all books about animals might be placed together. In 13 libraries, all books 14 by the same person may be placed together. Cabinets of cards list each book and tell where it can be found. People who live in the country may have trouble going to a city library. For these people there are librarians on wheels that 15 from place to place. | ||||
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