4.在是 (　　 )

　　 A．锐角三角形　　　 B．直角三角形　　　 C．钝角三角形　　　 D. 等腰直角三角形

3.已知是等差数列，，，则该数列前13项和等于(　　 )

A. 110　　 　　　　　 B.132　　 　　　 　　C. 156　　　　 　　　 D.100

2. 若，则的值为(　　 )

A. 　　　　　　B.　　　　　 C.　　　　　 D.

1.已知集合，，则集合=(　　 )

A．　 　 B．　 　 C．　　 D．

人们对健康越来越重视了，但我们的食品有很多不安全因素，很多蔬菜和水果都含有农药和化肥， 如果你是超市里“绿色蔬菜”柜台的促销员，请你向超市顾客介绍“绿色蔬菜”的特点，说明 “绿色蔬菜”对身体的好处。(120字左右)

British public library are linked by computers. If your　nearest library in London doesn't have the book you want　∕to﹨borrow it, the librarian will go on-line to see whether any　　other nearby library has(it). If no library in London have the book　　in store, the librarian will search it further, connecting　libraries in other city like Manchester. If a copy of the book(　is)　found, arrangements will be made for it to be sent to your　library within a day and two, and you will　be able to check it out. It is also possibly for readers to　borrow books from university and college　libraries even if we are not students.　　　　

British public library are linked by computers. If your　nearest library in London doesn't have the book you want　borrow it, the librarian will go on-line to see whether any　　other nearby library has. If no library in London have the book　　in store, the librarian will search it further, connecting　libraries in other city like Manchester. If a copy of the book　　found, arrangements will be made for it to be sent to your　library within a day and two, and you will　be able to check it out. It is also possibly for readers to　borrow books from university and college　libraries even if we are not students.