造林密度的作用主要表现在哪些方面？

       Robots are smart.  With their computer brains,  they help people work in dangerous places or do

difficult jobs. Some robots do regular jobs. Bobby, the mail carrier , brings mail to a large office building

in Washington, D. C.He is one of 250 mail carriers in the United States.

       Mr Leachim , who weighs two hundred pounds and is six feet tall,has some advantages as a teacher. One is that he does not forget details.  He knows each child's name, the parents' names and what each

child knows and needs to know. Except that,he knows each child's petsand hobbies. Mr Leachim does

not make mistakes.  Each child goes and tells him his or her name,  then dials and an ID number.   His

computer brain puts the child's voice and number together. He identifies the child with no mistakes. Then

he starts the lesson.

       Another advantage is that Mr Leachim is flexible. If the children need more time to do their lessons

they can move switches. In this way they can repeat Mr Leachim's lesson over and over again.When the

children do a good job,  he tells them something interesting abouttheir hobbies.  At the end of the lesson

the children switch Mr Leachim off.

1. What work can robots do?      

A. Safe work for people.

B. Usual work.

C. Very easy work.

D. Operate the computer

2. What is about Mr Leachim?   

A. He is very fat.  

B. He is very tall.

C. He is a teacher.  

D. He is a robot.

3.What is Mr Leachim's advantage as a teacher?   

A. Talk with his children

B. Remember the details.

C. He strict with his children.

D. Teach the lessons well.

4. Which one is the RIGHT order?

a. His computer brain puts the child's voice and number together.

b. Then he starts the lesson.

c. Each child does and tells him his or her name , then dials and an ID number.

d. He identifies the child with no mistakes.

A. c-d-b-a  

B. b-d-c-a  

C. c-a-d-b  

D. b-c-a-d

5. The word "flexible" means ______.

A. 严格的

B. 灵活的  

C. 和蔼的

D. 幽默的

如图所示，将密闭的相互连通的装置放在天平上，调节天平使之平衡。经过一段时间后，下列有关叙述正确的是(  )

A．指针偏左，食盐溶液一定变稀，烧碱潮解

B．指针偏右，食盐溶液一定饱和，烧碱潮解

C．指针偏左，食盐溶液一定变浓，烧碱潮解

D．指针偏右，食盐溶液一定变浓，烧碱潮解

过敏性紫癜为全身性毛细血管炎性疾病，其病理特点不包括以下哪一项

A．补体C3、IgA和纤维蛋白沉积
B．胶原纤维肿胀和坏死
C．IgG类免疫复合物沉积
D．血管内皮细胞肿胀
E．中性粒细胞浸润

每届亚运会所设各项运动至少需有（）个以上国家或地区参赛。

诊断液包括（）。

A、诊断抗原和诊断抗体

B、诊断毒素

C、诊断寄生虫和病毒

D、诊断动物传染病和鉴定病原微生物