造成前牙深覆盖的原因不包括() A.上颌相对前突 B.下颌相对后缩 C.上前牙唇倾

题型:单项选择题

问题:

造成前牙深覆盖的原因不包括()

A.上颌相对前突

B.下颌相对后缩

C.上前牙唇倾

D.下前牙唇倾

E.下切牙先天缺失

考点:广西口腔住院医师规范化培训口腔正畸学口腔正畸学题库
题型:单项选择题

芳香化合物A、B互为同分异构体,B的结构简式如图所示,A经①、②两步反应得C、D和E。B经①、②两步反应得E、F和H。上述反应过程、产物性质及相互关系如图所示。

提示:①苯酚既具有酸性,又可与羧酸发生酯化反应。

②酯在NaOH加热的条件下可水解为对应的羧酸钠和醇。

R1COOR2R1COONa+R2OH

(1)写出E的结构简式____________________________________________________。

(2)A有2种可能的结构,写出相应的结构简式。__________________________________________。

(3)F和小粒金属钠反应的化学方程式是_______________           _______________

(4)写出F与H在加热和浓H2SO4催化作用下发生反应的化学方程式_                    ________。反应类型是____________。

(5)写出F生成G的反应方程式________________                    ____

(6)在B、C、D、F、G、I化合物中,互为同系物的是__________________。

题型:单项选择题

以一种直接和()方式来表扬好的安全表现和行为,纠正不当的安全表现和行为是有效的现场安全指导,激励人们采取更安全的工作方式。

A、理解

B、嫉妒

C、粗暴

D、放纵

题型:单项选择题

土的含水量的测定方法有酒精燃烧法和();土的击实试验的主要目的是确定最大干密度和最佳含水量。

题型:单项选择题

加热炉燃料气系统应选用()式调节阀,而其进料系统应选用()式调节阀。

题型:单项选择题

More than 40 million Americans between the ages of 5 and 18 attend schools throughout the United States. About 2 million school-age children are taught at home. While home schooling offers an alternative to the school environment, it has become a controversial issue.

Many public school advocates take a harsh attitude toward home schoolers, perceiving their actions as the ultimate slap in the face of public education and a damaging move for the children. Yet, as public school officials realize they stand little to gain by remaining hostile to the home-school population, the hard lines seem to be softening a bit. Some public schools have moved closer to tolerance, and,even in some cases, are seeking cooperation with home schoolers. " We are becoming relatively tolerant of home schoolers. Let’s give the kids access to public school so they’ll see it’s not as terrible as they’ve been told, and they’ll want to come back, " says John Marshall, an education official.

Perhaps, but don’t count on it, say home-school advocates. Some home schoolers oppose that public school system because they have p convictions that their approach to education—whether fueled by religious belief or the individual child’s interests and natural pace—is best. Other home schoolers contend " not so much that the schools teach heresy, but that schools teach whatever they teach inappropriately." "These parents are highly independent and strive to ’take responsibility’ for their own lives within a society that they define as bureaucratic and inefficient. " says Van Gallon.

But Howard Carol, spokesman for America’s largest teachers union, argues that home schooling parents are trying to hide their children from the real world, says Van Gallon. " Maybe we are going to run into people with problems, people that have a drug problem, people that have an alcohol problem, and teenage pregnancy. We have many problems that happen in our society and many of the children are victims. But shielding the children from the real mix of what happens every day is denying them something that they are going to need later in life. " Mr. Carol also questioned the competence of parents as teachers though he admitted that some home schoolers do better academically. " We want to make sure that a student is not denied the full range of curriculum experiences and appropriate materials, especially now with the new technology that is being introduced and the costs involved there. "

" The success of home schooling has been documented in standardized test scores administered by public school officials, " says Frank Bernet, the executive director of the National Association of College Admission Councilors. " I know why they are doing it, but I wonder why they can’t work with school officials and teachers to make the school what they want it to be. " The response from home schoolers: " We have tried that. NOW it’s time to strike out on our own. \

It can be concluded from the passage that()

A. home schooling has become an important form of education in the U. S.

B. public schoolers and home schoolers reject each other vigorously

C. there is much controversy as to the emergence of home schooling

D. home schooling education is far inferior to public school education

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