初馏塔进料温度变化的原因有哪些？

实性肿瘤声像图特点，下列错误的是（）。

A.边界均不整齐、不光滑或不规则

B.常呈圆形、椭圆形或不规则

C.内部呈低、中等或高回声

D.可有后方衰减或声影，少数回声增强

E.侧方声影可有可无

已知等差数列{a_n}的前n项和为S_n，若a₃+a₆=20，则S₈等于（    ）。

阅读理解

     Americans are thinking about national education standards recently developed by teachers and other

education experts. The National Governors Association (NGA) and the Council of Chief State School

Officers (CCSSO) led the effort.

     The United States, unlike other nations, has never had the same school standards across the country. What is the reason? Education is not discussed in the Constitution.  That document limits the

responsibilities of the federal government. Other responsibilites,     like education, fall to each state.

     Local control of education probably was a good idea two hundred years ago. People stayed in the

same place and schools knew what students needed to learn. But today, people move to different  cities.

And some people work at jobs that did not exist even twenty years ago.

     Many American educators say that getting a good education should not depend on where you live.

They say that some states have lowered their standards in order to increase student scores on tests

required by the No Child Left behind Act.

     Kara Schlosser is communications director for the CCSSO. She says the new standards clearly state

what a student should be able to do to be successful in college and work.

     Forty--eight states have a1ready shown approval for the standards. Two states refuse to accept the

idea. Critics say that working toward the same standards in every state will not guarantee excellence for

all. Some educators in Massachusetts say adopting the national standards will hurt their students because

the state standards are even higher. Others say the change will be too costly, requiring new textbooks

and different kinds of training for teachers. Still others fear federal control.

     Supporters say the standards are goals and do not tell states or teachers how to teach. They also say

the federal government is not forcing acceptance. However, approving the standards will help states

qualify (取得资格)for some federal grant money.

1. What would be the best title for the passage?

A. Local Control of Education Standards out of Date

B. American National Education Standards under Consideration

C. Education Standards in Each State--Good or Bad.

D. Acceptance of the New Standards in the United States

2. Why is local control of education no 1onger a good idea today?

A. Because local standards are limited.

B. Because it is required by the federal government.

C. Because people today moves among states more often than before.

D. Because America has never had the same school standards throughout the  country.

3. Some people are against the nationa1 education standards because__________

A. the standards are higher than those of each state

B. they are not yet prepared for the new standards

C. the standards may prevent some students gaining excellence

D. they don't want the federal government to train their teachers

4. If a state agrees to accept the national standards, it will probably get ________.

A. more students      

B. advice on how to improve teaching

C. better textbooks    

D. money from the federal government

商陆药材的特征是（）

A.玉带束腰

B.乌云盖顶

C.云锦花纹

D.罗盘纹

E.水波纹

Internet所使用的网络协议体系是______。