一个直角三角形，三条边的长度分别是10厘米、8厘米、6厘米，这个三角形的周长是_

已知下 * * 个命题①方程x²-x+2=0的判别式小于或等于零；②矩形的对角线互相垂直且平分；③2是质数，其中真命题是（　　）

A．①和②

B．①和③

C．②和③

D．只有①

阅读理解。

     Jack and Hob are going to high school now. Jack wants to be an engineer. He is going to build roads,

bridges and house. Hob is interested in math and science, but he is going to study medicine. He wants to

be a doctor.

      Kate is good at music. She wants to be an artist. She is going to sing and dance for people. Joan wants

to be a woman astronaut (宇航员). She says," I am going to expore (探险) space (太空) some day." "What

do you want to be, Alice?"Joan asks me, "Oh, I want to be a teacher. When I grow up, I'm going to teach

in the countryside."

      Each of us is doing his or her best at school. I am sure we will do something good for our country.

1. ______ students are talking.[ ]

A. Two

B. Three

C. Four

D. Five

2. Who wants to be an artist? [ ]

A. Joan.

B. Jack.

C. Kate.

D. Alice.

3. Three students are interested in ______. [ ]

A. medicine

B. music

C. space

D.science

4. What does Joan want to be? [ ]

A. An astronaut.

B. A teacher.

C. A doctor.

D. An engineer.

5. Where does Alice want to teach?[     ]

A. On a farm.

B. In the countryside.

C. At home.

D. Abroad (国外).

（3分）实验室用过氧化氢溶液与二氧化锰混合制取氧气。若要制取1.6g氧气，理论上

消耗过氧化氢的质量是多少?

外汇业务会计科目的分类同人民币业务会计科目分类相同，划分为表内科目和（）两种。

门冬氨酸-α酮戊二酸可作为下列哪种酶反应的基质（）。

A.ALT

B.AST

C.ALP

D.GGT

E.AMY