气球可以带重物在空中飞行的原因是[ ] A.由于气球中气体的密度远远小于空气的密

题型:选择题

问题:

气球可以带重物在空中飞行的原因是[ ]

A.由于气球中气体的密度远远小于空气的密度,只要气球中充满这种气体,它都可以上升

B.只有在气球排开的气体的重力大于气球及它所带重物的重力才能上升

C.气球只要充足气总可以上升

D.气球上升与充入气体的密度无关

考点:浮力及阿基米德原理
题型:选择题

下列腧穴中,治疗痛经首选穴是()

A.隐白

B.太白

C.公孙

D.血海

E.地机

题型:选择题

正常注水井每季度洗井1次,停注()h必须洗井。

A、12

B、24

C、36

D、48

题型:选择题

     Each new school year brings fresh reminders of what educators call the summer learning gap.Some call it the summer learning setback Put simply, it means the longer kids are out of school,the more they forget.The only thing they might gain is weight.

Most American schools follow a tradltional nine-month calendar with winter and spring breaks and about ten weeks of summer vacation.Some schools follow a year-round calendar. They hold classes ror about eight weeks at a time,with a few weeks off in between.The National Association for Year-Round Education says there were fewer than 3,000 such schools at last count.They were spread among forty-six of the tifty states.

But many experts point out that the number of class days in a year-round school is generally the same as in a traditional school.Brenda McLaugblin is research director at the National Center for Summer Learning at Johns Hopkins University.She says studies of year-round schooling have not found strong learning gains.Lead researcher Paul von Hippel said,“Year-round schools don’t really solve the problem of the summer learning setback.They simply spread it out across the year.”

Across the country, research shows that students from poor families fall farther behind over the summler than other students.Experts say this can be prevented.They note that many schools and local governments offer programs that can help.

But calling them“summer school”could be a problem.The director of the summer learning center at Johns Hopkins, Ron Fairchild, said research with groups of different parents in Chicago and Baltimore found that almost all strongly disliked the term“summer school”.In American culture,the idea of summer vacation is connected to beliefs about freedom and the joys of childhood.The parents welcomed other terms like“summer camp。”“extra time”and“hands-on learning.”

小题1:According to the first paragraph,the summer learning gap     

A.helps children to gain weight

B.leads children to work harder

C.improves children’s memories

D.affects children’s regular studies小题2:Compared to traditional schools,students in the year-round ones     

A.perform better and have more learning gains

B.have much less time for relaxation every year

C.have generally the same number of class days

D.hold more classes with more free weeks off小题3:Which of the following statements is true?

A.Students from poor families often fall behind after the vacation.

B.Year-round schools can solve the problem of the learning gap

C.There are schools in each state following a year-round calendar

D.Nothing can help the students who fall behind after the vacation.小题4:Why did almost all parents dislike the term“summer school”?

A.They are worried about the quailty of the“summer school”

B.They cherish the children’s rights of freedom very much.

C.They want their children to be forced to make up the gap.

D.They can’t afford to the further study during the vacation.小题5:What would be the best title of this passage?

A.Opening Summer Camps

B.Forbidding Summer Schools

C.Minding the Summer Learning Gap

D.Reforming Year-Round Education

题型:选择题

滑车神经支配的是______

A.外直肌
B.上斜肌
C.上直肌
D.下直肌
E.内直肌

题型:选择题

1841年首次承认邻接权的是()

A.英国

B.中国

C.美国

D.意大利

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