问题 实验题

按照我国交通管理的规定,“红灯停、绿灯行、黄灯预备。”小明在科技活动中设计了一个实验电路,如图所示。用以模拟十字路口的红绿灯控制。请你认真分析后填空:

(1)当单刀多掷开关接通位置“1”时,有_______个灯发光,发光灯的连接采用的是_______联方式。

(2)当开关接通位置“3”时,允许__________方向的车辆通行。(选填“东西” 或“南北”)

答案

(1)4,并

(2)东西

阅读理解

阅读理解。

     Millions of Americans return from long-distance trips by air, but their luggage doesn't always come

home with them. Airline identification tags(标签) can come loose, and the bags go who-knows-where.

And passengers leave all kinds of things on planes.

     The airlines collect the items and, for 90 days, attempt to find their owners. They don't keep them,

since they're not in the warehouse business. And by law, they cannot sell the bags, because the airlines

might be tempted to deliberately misplace luggage.

     So once insurance companies have paid for lost bags and their contents, and they no longer belong

to passengers, a unique store in the little town of Scottsboro, Alabama, buys them. The "Unclaimed

Baggage Center," is so popular that the building, which is set up like a department store, is the

number-one tourist attraction in all of Alabama. More than one million visitors stop in each year and

take one of the store's shopping carts on a hunt for treasures.

     Each day, clerks bring out 7,000 new items, and veteran(老练的)shoppers rush to paw over them.

You can find everything from precious jewels to hockey sticks, best-selling novels, leather jackets,

tape recorders, surfboards, even half -used tubes of toothpaste.

     The store's own laundry washes or cleans all the clothes found in luggage, then sells them. The

Unclaimed Baggage Center has found guns, illegal drugs and even a live rattlesnake.

     The store has a little museum where some of its most unusual acquisitions(获得物) have been

preserved. They include highland bagpipes, a burial mask from an Egyptian pharaoh's tomb, and a

medieval suit of armor.

     Statistics indicate that less than one-half of one percent of luggage checked on U.S. carriers is

permanently lost and available to the store.

1. Paragraph1 shows that many passengers lose their luggage because______.

A. they are forgetful

B. they are in a hurry

C. there is no lost and found office in many airports

D. the owners of some luggage can't be identified

2. The reason why the airlines cannot sell the bags is that ______.

A. they have to find the owners 

B. they are likely to make a profit on the bags on purpose 

C. some bags are expensive

D. they have to keep the bags as long as possible

3. The Unclaimed Baggage Center is very popular because______.

A. there's a large variety of goods.

B. all the things there are very cheap.

C. visitors may purchase something undervalued.

D. Visitors will enjoy some amusing activities there.

4. What can we infer from the passage? 

A. A little museum will keep all the precious unclaimed baggage.

B. The percentage of passengers who lose their baggage for ever is small.

C. The things in the Unclaimed Baggage Center are articles for daily use.

D. People are not allowed to buy the illegal things in the store.

5. What is the main purpose of the passage? 

A. To introduce how the unclaimed baggage in the airports is handled in America.

B. To introduce an attractive place to tourists.

C. To remind passengers of taking care of their baggage.

D. To advise the airlines to find the owners of the unclaimed baggage.

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