石油沥青的化学组分中，蜡的存在会降低沥青路面的抗滑性。( )

已知长江比黄河长836千米，黄河长度的6倍比长江5倍多1284千米，设长江、黄河的长分别为x、y千米，则正确列出方程组为______．

阅读理解。

     Children don't come with an instruction manual (手册),but now their grades in school do! Finally,

parents can stop worrying about what their child's next school year will bring and get a glimpse of what's

coming.

     Education.com,an easy-to-use,one-stop online destination with over 4,000 articles,that helps parents

and educators take an ever more active role in their children's education,unveiled Grade Specific Cheat

Sheets for grades pre-school through grade 5.From academic expectations,developmental milestones,and

typical social issues,to fun learning activities that literally bring it all home,parents can now find it all in one

place.

     "As the school year approaches,parents struggle to find time to adequately prepare themselves and

their children for what's ahead," said Ron Fortune,CEO of Education.com."Every grade is different.

Whether it's helping parents understand what their third grader should be reading or how they should be

talking to their teen about peer pressure,our goal is to provide parents with a grade and developmental

stage-specific user manual that helps parents find authoritative information as quickly as possible."

     The start of a new grade means many new questions.Now,a parent with a child about to embark

(开始) on a new school year can go to Education.com's new Grade Specific Cheat Sheets and find

age-specific information and content including what their child should be learning in math,reading,writing,

and science,as well as physical and language milestones.Parents can find over forty articles per grade,on

everything from peer relationships to self-esteem,how gender affects development,to ideas for using

goldfish crackers for math practice or making a homemade fossil.

     Education.com's new Grade Specific Cheat Sheets provide parents with articles and content from

trusted sources such as teachers,child psychologists,parents,and guidance counselors.  

1.The passage wants to tell us __________.

A. something about Education.com

B. how to cheat in the exam

C. new studying method for children

D. cheating is a good thing in the school

2.The goals of Education.com are the following except __________.

A. helping parents and educators educate children

B. providing parents with authoritative information

C. providing children with some cheating skills

D. giving parents some useful articles

3.The role of Education.com is __________.

A. passive          

B. big          

C. small        

D. active

4.From the passage,we can know __________.

A. the content includes what should be learned in many subjects

B. the content does not come from trusted sources

C. the content is intended mainly for the children

D. the content is not related with pre-school students

5.The words "unveil" in the second paragraph is closest to __________ in meaning.

A. cover          

B. uncover        

C. discover    

D. invent

正常人在30岁前，角膜内皮细胞平均密度为

A．1000～2000个／mm²

B．2000～3000个／mm²

C．3000～4000个／mm²

D．4000～5000个／mm²

学校美育计划性强的特征体现了（）

A．教师主导

B．目的性

C．合理性

D．排除随意性

E．系统性

煤矿安全生产“八查”的主要内容有哪些？