已知△ABC中,∠C=60°,c=2,则a+b的取值范围为( ) A.(2,4]

题型:选择题

问题:

已知△ABC中,∠C=60°,c=2,则a+b的取值范围为(  )

A.(2,4]

B.[2,4]

C.(3,4]

D.[3,4]

考点:解三角形
题型:选择题

统计表示法的分类中不包括()。

A.效果表示法

B.分组表示法

C.对比表示法

D.动态表示法

E.依存表示法

题型:选择题

薄荷与柴胡的共同功效是()

A.解表

B.疏肝

C.透疹

D.止痛

E.升阳

题型:选择题

Humans have sewn by hand for thousands of years. It was said that the first thread was made from animal muscle and sinew (肌腱). And the earliest needles were made from bones. Since those early days, many people have been involved in the process of developing a machine that could do the same thing more quickly and with greater efficiency.

Charles Wiesenthal, who was born in Germany, designed and received a patent on a double-pointed needle that eliminated the need to turn the needle around with each stitch (缝合) in England in 1755. Other inventors of that time tried to develop a functional sewing machine, but each design had at least one serious imperfection.

Frenchman Barthelemy Thimonnier finally engineered a machine that really worked. However, he was nearly killed by a group of angry tailors when they burned down his garment factory. They feared that they would lose their jobs to the machine.

American inventor Elias Howe, born on July 9, 1819, was awarded a patent for a method of sewing that used thread from two different sources. Howe’s machine had a needle with an eye at the point, and it used the two threads to make a special stitch called a lockstitch. However, Howe faced difficulty in finding buyers for his machines in America. In frustration, he traveled to England to try to sell his invention there. When he finally returned home, he found that dozens of manufacturers were adapting his discovery for use in their own sewing machines.

Isaac Singer, another American inventor, was also a manufacturer who made improvements to the design of sewing machines. He invented an up-and-down-motion mechanism that replaced the side-to-side machines. He also developed a foot treadle (脚踏板) to power his machine. This improvement left the sewer’s hands free. Undoubtedly, it was a huge improvement of the hand-cranked machine of the past. Soon the Singer sewing machine achieved more fame than the others for it was more practical. It could be adapted to home use and it could be bought on hire-purchase. The Singer sewing machine became the first home appliance, and the Singer company became one of the first American multinationals.

However, Singer used the same method to create a lockstitch that Howe had already patented. As a result, Howe accused him of patent infringement (侵犯). Of course, Elias Howe won the court case, and Singer was ordered to pay Howe royalties (版税). In the end, Howe became a millionaire, not by manufacturing the sewing machine, but by receiving royalty payments for his invention.

小题1:Barthelemy Thimonnier’s garment factory was burned down because __________.

A.people did not know how to put out the fire

B.Elias Howe thought Thimonnier had stolen his invention

C.the sewing machines couldn’t work finally

D.workers who feared the loss of their jobs to a machine set fire小题2:Why did the court force Isaac Singer to pay Elias Howe a lifetime of royalties?

A.Because the judge was against Singer for his unfriendly attitude.

B.Because Howe had already patented the lockstitch used by Singer.

C.Because Singer had borrowed money from Howe and never repaid it.

D.Because Singer and Howe had both invented the same machine.小题3:Which of the following would be the best title for this passage?

A.A Stitch in Time Saves Nine

B.The Case between Howe and Singer

C.Patent Laws on the Sewing Machine

D.The Early History of the Sewing Machine

题型:选择题

一音教

题型:选择题

()强调从教育对象的实际出发,区别对待,有的放矢。

A.坚持主体性原则

B.坚持调查研究与正确引导相结合的原则

C.坚持科学灌输与互动交流相结合的原则

D.坚持因人施教的原则

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