Across the United States, there are several places where two independent towns grew together to become one city — but kept both their names.
WinstonSalem is one of them. It’s a midsized city in what’s called the plateau（high land）, between the Atlantic Coast and the inland mountains in the state of North Carolina. The Winston part is a relatively new place, founded early this century. It’s home to the nation’s biggest openair tobacco market.
The giant R.J. Reynolds Tobacco Company’s headquarters is in WinstonSalem, and Winston is the name of one of Reynolds’bestknown cigarette brands. Fastgrowing Winston soon surrounded the much older town of Salem, so in 1913, people in the area voted to combine them into a single place.
From a historical and tourist point of view, Salem, or Old Salem, as it’s called today, is the interesting and unusual part of town.
Salem was founded in the 1700s by the Moravians. They spoke German, and their community was religiously based, with single men and single women living apart in separate dormitories. The Moravians greatly valued women’s work and brainpower. In fact, one of the nation’s oldest boarding schools for young women— the Moravians’Salem Academy founded in 1772 — is still in operation.
Over the years, Salem lost its Moravian character. That all changed, though, when a nonprofit group began to rehabilitate the historic area. These days Old Salem is what’s called a living history museum, with exhibits, music, and tours of 18th-century houses, taverns and Moravian dormitory buildings just seven blocks from the tallest skyscraper in Winston-Salem.
The historic community is booming again. Just as R. J. Reynolds is taking in millions of dollars making cigarettes across town, Old Salem is generating about S| 15 million a year in tourism revenue and donations.
61. From the passage we can know that____________.
A. Winston-Salem is the name of a city
B. Salem is home to the tobacco market
C. the city Winston-alem has two names
D. Old Salem is the name of a tobacco brand
62. It can be inferred from Paragraph 3 that__________.
A. the two cities benefited each other
B. Salem developed faster than Winston
C. R.J. Reynolds Company has moved into Salem
D. the combination meets the wishes of the people
63. The city Salem is special for its__________.
A. boarding school B. lifestyle and tradition
C. respect for brainpower D. religious belief
64. The underlined word “rehabilitate” in Paragraph 6 is closest in meaning to “_________”.A. reconstruct B. evaluate C. enlarge D. decorate
65. What will probably be talked about in the following part?
A. Some other attractions in Winston-Salem.
B. How Winston makes profits from tourism.
C. Other examples of cities combined by two parts.
D. Something about the boarding school for women.
m、内半径为R1的同心环形磁场区域，磁感应强度大小均为B＝0.5 T，方向相反，均垂直于纸面，一带正电粒子从平行极板下板P点静止释放，经加速后通过上板小孔Q，垂直进入环形磁场区域，已知点P、Q、O在同一竖直线上，上极板与环形磁场外边界相切，粒子比荷q/m＝4×107 C/kg，不计粒子的重力，且不考虑粒子的相对论效应，求：
2≤5×106 V