题目

1mol乙烯与氯化氢在一定条件下完全加成后，再与氯气在一定条件下发生取代，整个过程最多需要氯气为（    ） A.1mol     B. 4mol    C. 5mol    D. 6mol 答案：CThe snow has paralysed(使瘫痪) transport in China during the country’s most important vacation period, the celebration of the Chinese New Year. Not only have transport delays hindered personal trips, but they have also slowed the delivery of fresh produce to markets. Consequently, in Zhengzhou, the capital city of the Henan province, tomato prices have doubled, and the cost of 47 other vegetables has increased by 36%, as reported by local media at the end of January.      According to an inside PR source, “wholesalers in Beijing were quoted as saying that only about 20% of the usual fresh vegetable supplies were reaching the city.” As an Asian country with a diet based on fresh produce, the shortage of vegetables and the rise in prices is not only affecting fresh food producers, but also the final consumers.      In terms of production, this is the worst snow disaster to hit China in the last 50 years, affecting a total of 9.4 million hectares of farmland in the country, according to a report published on 4 February 2008 by Feng Tao of Xinhua News, at the Chinese government website. Most of the crops devastated（毁坏）by the frost are located in the middle and lower reaches of the Yangtze River, the traditional natural border between North and South China. Chen Xiwen, Director of the Office of the Central Leading Group on Rural Work, pointed out at the end of last week that “the blizzard disaster in the south has had a severe impact on winter crops, and the impact on fresh vegetables could be catastrophic in certain areas”, as stated in the Xinhua News report.      The Chinese government has been quick to take extreme measures. The Chinese Ministry of Agriculture (MOA) has sent 13 teams of experts to 8 of the areas most seriously affected by the harsh weather. The aim of this initiative is to provide farmers with technical assistance to minimize their losses. From this passage, we can know that the snow happened _____.    A. During the Spring Festival    B. In the coldest days of the winter    C. In the North of China.    D. It’s not mentioned here. What’s the meaning of the underlined word in paragraph four?    A. worst  B. snowstorm  C. cold weather  D. biggest This passage mainly tells us _____ .    A. The snow in the south of China caused many problems.    B. The effect of the snow in the south of China on the fresh food    C. The snow in the south of China slowed the delivery of fresh produce to markets.    D. The Chinese government has taken extreme measures to help the suffered farmers. The Chinese Ministry of Agriculture (MOA) has sent 13 teams of experts to 8 of the areas to _____ .    A. help the farmers plant crops          B. give money to the farmers    C. give directions to the farmers with their technic（技术；技巧）.    D. deliver crops for the farmers.