一个小正方形的边长是2厘米,它的周长是______厘米.用4个这样的小正方形拼成

题型:解答题

问题:

一个小正方形的边长是2厘米,它的周长是______厘米.用4个这样的小正方形拼成大正方形,大正方形的周长是______厘米.

考点:图形的拼组(剪)
题型:解答题
(1)6:12
(2)0.2:0.05
(3)
9
20
9
2

(4)21:42
(5)
3
4
9
16

(6)
24
25
48
50
题型:解答题

物理实验中,常用一种叫做“冲击电流计”的仪器测定通过电路的电量.如图所示,探测线圈与冲击电流计串联后可用来测定磁场的磁感应强度.已知线圈的匝数为n,面积为s,线圈与冲击电流计组成的回路电阻为R.若将线圈放在被测匀强磁场中,开始线圈平面与磁场垂直,现把探测圈翻转180°,冲击电流计测出通过线圈的电量为q,由上述数据可测出被测磁场的磁感应强度为 

[ ]

A.qR/S

B.qR/nS    

C.qR/2nS

D.qR/2S

题型:解答题

A conventional teacher’s licensee usually requires a university degree in education plus an unpaid term of practice teaching. This has never made much sense. It excludes bright students who take degrees in other subjects, and might teach those subjects; it is costly and time-consuming for career-switchers, who must wait a year or more before they can enter a classroom; it is so rigid that private-school teachers or university professors with years of experience have to jump through hoops before they can start teaching in a state school. And there is virtually no evidence that it creates better teachers. For all that, it is ply backed by schools of education, which have a monopoly of teacher-training, and by teachers’ unions, whose members make more money when it is artificially hard for others to get into the profession.

Now, some 45 states and the Districts of Columbia offer an "alternative route" to a teacher’s licensee, up from only a handful in the 1980s. Alternative certification (AC) generally allows individuals with a university degree to begin teaching immediately after passing an entrance examination. These recruits, watched over by a mentor teach the subject they studied at university, and take education courses at a sponsoring university while drawing their salaries.

The traditional sort of American teacher is likely to be young, white and female. Alternative certification attracts more men and more non-whites. In Texas, for instance, roughly 90% of public-school teachers are white, but 40% of those who have joined through alternative certification are non-whites. The AC route also draws teachers willing to go where they are most needed. A survey of Troops to Teachers, a program that turns exsoldiers into public-school teachers (" Proud to serve again"), found that 39% of those taking part are willing to teach in inner-city schools, and 68% in rural areas.

Are they good teachers Officialdom is reluctant to release the details which might answer that question for certain. But anecdotal evidence suggests they do well. In New Jersey, which has been running this sort of program since 1984, rich districts, which can afford to be choosy, consistently hire more AC teachers than poor districts do. In Houston, Texas, where the Teach of America program (TFA) puts recent university graduates into poor communities as teachers, the most effective teachers are generally the TFA ones. " School principals are our biggest fans," Wendy Kopp, TFA’s president, says proudly.

So why not scrap the cumbersome teacher-licensing laws Frederick Hess, a professor at the University of Virginia, has written a paper for the Progressive Policy Institute arguing that teacher-licensing ought to be stripped to the bare essentials. Prospective teachers should be required only to hold a college degree, pass a test of essential skills, and be checked to make sure they do not have a criminal background. Other training is important, argues Mr. Hess, but the market, not state legislators, should decide what that training looks like. This notion of "competitive certification" has drawn favorable attention from the Bush administration.

What does the author suggest when he calls for "competitive certification" ( Line 7—8, Para.5 )()

A. Simplify teacher-licencing

B. Operate education like a market

C. Scrap unified education standard

D. Make entry easy for prospective teachers

题型:解答题

有两列沿相反方向传播的相干波,其波动方程分别为y1=Acos2π(vt-x/λ)和y2=Acos2π(vt+x/λ)叠加后形成驻波,其波腹位置的坐标为:()

A.x=±kλ

B.x=±1/2(2k+1)λ

C.x=±1/2kλ

D.x=±(2k+1)λ/4(其中k=0,1,2,…)

题型:解答题

简述森林立地质量评价方法。

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