在纸上剪一个很小的“△”形孔,让太阳光垂直照射到“△” 形孔上,那么地面上形成的

题型:选择题

问题:

在纸上剪一个很小的“△”形孔,让太阳光垂直照射到“△” 形孔上,那么地面上形成的光斑是:(   )

A.“▽” 形的

B.圆形的

C.“△”形

D.无法确定

考点:光的直线传播的应用
题型:选择题

阅读短文,选择正确答案。

     Have you ever noticed an advertisement which says "Learn a foreign language in six weeks, or your money

back! From the first day your pronunciation will be excellent. Just send …" and so on? Of course, it never

happens quite like that. The only language that is easy to learn is the mother tongue. And think how much

practice that gets! Before the Second World War people usually learned a foreign language in order to read the

literature (文学) of the country. Now speaking the foreign language is what most people want. Every year many

millions of people start learning one. How do they do it? Some people try at home, with books and tapes; some

use radio or television programmes; others go to evening classes. If they use the language only two or three

times a week, learning it will take a long time, like language learning at school. A few people try to learn a

language fast by studying for six or more hours a day. It is clearly easier to learn the language in the country

where it is spoken. However, most people cannot afford this, and for many it is not necessary. They need the

language in order to do their work better. For example, scientists and doctors mainly need to be able to read

books and reports in the foreign language. Whether the language is learned quickly or slowly, it is hard work.

Machines and good books will help, but they cannot do the students work for him.

1. In the advertisement it is possible for a person to learn a foreign language _______. [ ]

A. more than two month

B. half a year

C. six months

D. less than two month

2. Before the Second World War people learned a foreign language in order to ______. [ ]

A. speak to each other

B. listen to the radio

C. read something they didn't know

D. write the literature of the other country

3. The easiest way for us to learn a foreign language is _______.[ ]

A. using the language six or more hours a day

B. learning the language at school

C. studying the language in the foreign country

D. reading the foreign stories as many as possible

4. Most people now learn a foreign language to ________.[ ]

A. read books and reports in a foreign language

B. talk to foreign friends

C. go to the other country to learn a language well

D. try their best to work better

5. The passage tells us that _______. [ ]

A. the more you spend, the quicker you'll learn the language

B. it is possible for you to learn a foreign language in six weeks

C. it is not good for you to learn a foreign language by yourself

D. the quicker you learn a foreign language, the more you must pay for it

题型:选择题

小明和小红两人共带200元钱去购物,购完后两人剩下的钱数正好相等.已知小明花去的钱数与他原来的钱数的比是3:7,小红花去的钱数和她原来钱数的比是9:13,小明花去多少钱?

题型:选择题

我国的公有制经济包括       

[ ]

①社会主义初级阶段的基本经济制度 

②我国的非公有制经济

③混合所有制经济中的国有成分和集体成分 

④国有经济和集体经济

A.①②   

B.②③   

C.①③   

D.③④

题型:选择题

化学与我们的生活密切相关,请你结合生活经验填空:

(1)炒菜用的铁锅手柄是用__________(填“热固性”或“热塑性”)塑料做成的;

(2)“火立熄”是一种新型的家用灭火用品,它接触到火焰3~5秒后炸开,释放的粉末覆盖在燃烧物上,同时放出不可燃气体,使火熄灭,其灭火原理是____________________;

题型:选择题

成组资料比值比的分子为:()。

A.暴露组某病某年发病率

B.暴露组某病某日患病率

C.病例组中暴露者数与对照组中非暴露者数的乘积

D.病例组中非暴露者数与对照组中暴露者数的乘积

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