问题 选择题

绕在同一铁芯上的线圈Ⅰ、Ⅱ按图所示方法连接,G为电流计,则(   )

A.保持开关S闭合状态,G的示数不为零

B.开关S闭合瞬间, G的示数不为零

C.保持开关S闭合,移动变阻器R0滑动触头的位置,G的示数为零

D.断开开关S的瞬间,G的示数为零

答案

答案:B

题目分析:当开关保持闭合状态时,由于线圈Ⅰ中的电流恒定,导致穿过线圈Ⅱ的磁通量不变,所以G的示数为零;当开关保持闭合状态时,移动变阻器R0滑动触头的位置,造成线圈Ⅰ中的电流变化,导致穿过线圈Ⅱ的磁通量变化,故G的示数不为零;在开关闭合或者断开瞬间,由于线圈Ⅰ电流变化,导致穿过线圈Ⅱ的磁通量变化,故G的示数都不为零。综上所述,B正确

阅读理解

Dubai is a city of big business, expensive hotels, skyscrapers (摩天楼), and shopping malls. In the early 20th century, Dubai was a successful trading port. People from the world stopped in Dubai to do business. But it was still a small city, and most people lived as fishermen and businessmen. Then in 1966, oil was discovered. This brought a lot of money into the area, and soon Dubai began to change.

Today Dubai is one of the world’s most important business centers. In fact, each year the city gels its money mainly from business, not oil.

Recently Dubai has attracted more and more visitors from abroad. They come to relax on its beaches, and every year, millions visit just to go shopping!

Dubai is also one of the world’s fastest growing cities. Many tall buildings are built in months. The city also has many man-made islands. One of these, the Palm Jumeirah, is like a palm tree (棕桐树) and is very beautiful.

The city is still an amazing mix (混合体) of people from different countries. The people from 150 countries live and work in Dubai, and foreigners now outnumber Dubai natives ( 本地人) by eight to one!

Many people welcome the city’s growth. But an increasing number of Dubai natives worry about the speed of change. As a Dubai native says, “We must always remember where we came from. Our kids must know we worked very, very hard to get where we are now, and there’s a lot more work to do.”

小题1:Why did people stop in Dubai in the early 20th century?

A.To relax

B.To buy oil.

C.To go shopping.

D.To do business.小题2:Which of the following is NOT true?

A. Dubai has created many man-made islands.

B. There are many foreigners working in Dubai.

C Many international visitors come to Dubai every year

D. Dubai now gets money mainly from selling oil.

小题3:What does the underlined word “outnumber” mean?

A.To be smaller in size than another group.

B.To be more in number than another group.

C.To be bigger in area than another group.

D.To be smaller in area than another group.小题4:In the last paragraph, what does the underlined part mean?

A.We should always visit Dubai,

B.We should learn from foreigners.

C.We must always remember our past.

D.We must only think about the future.小题5:What’s the main idea of the passage?

A.Dubai is growing very fast.

B.Dubai was a big city before 1966.

C.Many tall buildings are built in months.

D.Many tourists come to relax on Dubai’s beaches.

填空题