题干

小林化简 (
a
+
2
a
2
−
2
a
−
a
−
1
a
2
−
4
a
+
4
)
÷
a
−
4
a
3
 后说:“在原分式有意义的前提下,分式的值一定是正数.”你同意小林的说法吗?请说明理由
上一题 下一题 0.0难度 选择题 更新时间:2018-05-21 08:04:06

答案(点此获取答案解析)

解:

同意小林的说法,理由如下:

原式 =a+2a(a−2)

同类题2

阅读下列材料,结合所学知识回答问题。

材料一:“一带一路”高峰论坛和G20杭州峰会上,***主席提出加强经济政策协调,挖掘新动能,包容和联动发展,为当前世界经济发展开出了 “中国药方”。G20杭州峰会文艺晚会,把《春江花月夜》、《高山流水》等成国传统曲目与《天鹅湖》、《月光》等国外曲目诗情演绎,既彰显杭州特色、中国气派和世界大同,又契合“创新活力、联动、包容”的峰会主题。

推动“一带一路”建设,我们要发挥文化先行的优势,充分发掘沿线国家深厚的文化底蕴,以包容的心态推动沿线国家文化交流、借鉴与融合,从而促进沿线国家经济文化的共同发展。

材料二:中国古典园林因其独特的造园艺术被西方国家所推崇。目前,已有40多座苏州园林先后落户30个国家及地区,漂洋过海传播中国魅力。“异地落户”的苏州园林,水榭、亭台、拱桥、长廊、漏窗等传统江南园林建筑元素应有尽有,布局精巧韵味独特,亭台楼榭绿树掩映,处处透出大自然的情趣。同时,在建设过程中注重融入当地文化元素,采用全钢结构,引入纳米、碳纤维等多种技术提升中国园林的技术含量。中国工匠秉持“传统与现代、中国与外国、人工与自然和谐共处”的理念,使两者相得益彰,打造了一个个园林精品,受到越来越多海外人士的青睐。

同类题3

     In the 1920s and 30s the airlines were just beginning. It was unusual for people to travel by air because it was expensive and dangerous. In those days, there were no flight attendants to look after the passengers. Young men ,or “stewards” helped the passengers onto the airplane and carried the passengers' luggage(行李)but they did not provide food and drinks. But then in 1930,a woman called Ellen Church invented the “stewardess”.
      Ellen Church was born in 1904 on a farm in Iowa. She was a different child. She didn't want to work on a farm or marry a farmer —she wanted a more adventurous(冒险的)life. Ellen studied to be a nurse at the University of Minnesota and then got a job in a hospital. For the next few years she stayed at the hospital but also took flying lessons and got her pilot's license.
      Ellen was twenty-five years old when she first got in touch with Boeing Air Transport. She loved flying but she understood that airlines were a man's world. Although women like Emelia Earheart were becoming famous, she realized it was impossible for a woman to have a career as a pilot .But she had another idea. Most people were frightened of flying because. flying was still an unreliable(不可靠的) way to travel. There were often delays(延误),many crashes and the bad weathers made many passengers sick. Ellen thought nurses could take care of passengers during flights and B.A.T. agreed.
      The young woman from Iowa and seven other nurses became the first air stewardesses.
At first pilots were unhappy because they did not want stewardesses on airplanes, but passengers loved the stewardesses. In 1940 there were around 1000 of them working for different airlines. The early “stewardesses” had to be under twenty-five-year-old, single and slim. When a woman joined an airline, she had to promise not to get married or have children. It was hard job and not well paid. They worked long hours and earned $1 an hour.
     In the 1970s, stewardesses were unhappy in their job and airlines had to make some changes. Since the 1970s, “stewardesses” have been called flight attendants. They are well paid and work fewer hours than in the past.