如图,两质量均为m的小球,通过长为L的不可伸长轻绳水平相连,从h高处自由下落,下

题型:不定项选择

问题:

如图,两质量均为m的小球,通过长为L的不可伸长轻绳水平相连,从h高处自由下落,下落过程中绳处于水平伸直状态,若下落时绳中点碰到水平放置的光滑钉子O,重力加速度为g,则

[ ]

A.小球从开始下落到刚到达最低点的过程中机械能守恒

B.从轻绳与钉子相碰到小球刚达到最低点过程,重力的功率先减小后增大

C.小球刚到最低点速度大小为

D.小球刚到达最低点时绳中张力为

考点:功率机械能守恒定律
题型:不定项选择

解不等式 |x-5|-|2x+3|<1

题型:不定项选择

生物安全等级4级(P4)的媒质是指()。

A.普通无害细菌、病毒等微生物

B.条件致病性细菌、病毒等微生物

C.一般性可致病细菌、病毒等微生物

D.烈性/致命细菌、病毒等微生物,但感染后可治愈

E.烈性/致命细菌、病毒等微生物,感染后不可治愈

题型:不定项选择

在履行行政职能中,通过制定工作目标、规定奖惩办法,根据各类管理主体的实际工作业绩和考核决定升迁、兑现奖励与惩罚,以刺激管理主体积极性、提高管理效率,体现的是()管理运行机制。

A.竞争

B.反馈

C.约束

D.激励

题型:不定项选择

Reading is the key to school success and, like any skill, it takes practice. A child learns to walk by practising until he no longer has to think about how to put one foot in front of the other. A great athlete practises until he can play quickly, accurately, without thinking. Tennis players call that ”being in the zone.” Educators call it “automaticity”.

A child learns to read by sounding out the letters and decoding the words. With practice, he stumbles less and less, reading by the phrase. With automaticity, he doesn’t have to think about decoding the words, so he can concentrate on the meaning of the text.

It can begin as early as first grade. In a recent study of children in Illinois Schools, Alan Rossman of Northwestern University found automatic readers in the first grade who were reading almost three times as fast as the other children and scoring twice as high on comprehension tests. At fifth grade, the automatic readers were reading twice as fast as the others, and still outscoring them on accuracy, comprehension and vocabulary.

“It’s not I.Q. but the amount of time a child spends reading that is the key to automaticity,” according to Rossman. Any child who spends at least 3.5 to 4 hours a week reading books, magazines or newspapers will in all likelihood reach automaticity. At home, where the average child spends 25 hours a week watching television, it can happen by turning off the set just one night in favor of reading.

You can test your child by giving him a paragraph or two to read aloud—something unfamiliar but appropriate to his age. If he reads aloud with expressions, with a sense of the meaning of the sentences, he probably is an automatic reader. If he reads haltingly, one word at a time, without expression or meaning, he needs more practice.

13.The first paragraph tells us            .

A.what automaticity is                    B.how accuracy is acquired

C.how a child learns to walk               D.how an athlete is trained

14.The Illinois study shows that the automatic reader’s high speed         .

A.costs him a lot of work            B.affects his comprehension

C.leads to his future success         D.doesn’t affect his comprehension

15.A bright child         .

A.also needs practice to be an automatic reader

B.always achieves great success in comprehension tests

C.becomes an automatic reader after learning how to read

D.is a born automatic reader

16.The main idea of the passage is           .

A.how to score high on comprehension tests

B.reading is the key to school success

C.how to test your child’s reading ability

D.automaticity is important for efficient reading

题型:不定项选择

区域经济协调发展

更多题库