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苯环上原有的取代基对新取代导入苯环上的取代基的位置有一定的影响,其规律是(1)苯环上新导入的取代基所占的位置主要决定于原有取代基的性质;(2)可以把原有取代基分成两类:第一类取代基主要使新导入的取代基进入苯环的邻位和对位,如—OH、—CH3(或烃基)、—Cl、—Br、—O—COR等。第二类取代基主要使新导入的取代基进入苯环的间位,如—NO2、—SO3H、—CHO等。请写出下图中②④⑤三步反应的化学方程式。

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    One talented father created the tag “Dadfact” in an effort to persuade his child into eating their sandwiches using information that might not be completely reliable.

    Flying is fine if you want to save time, but nothing beats the railway for a relaxing and down-to-earth journey. The Zhengzhou---Xuzhou and Xi'an---Fuzhou high-speed railways put into operation in September mark a connection of high-speed railways in China's eastern and middle-western regions, and they have brought out some of the country's best landscapes and cuisines.

    Here are four signature dishes(招牌菜) that you shouldn't miss as you travel along the railways.

Yangrou Paomo, Xi'an

    If one dish could represent Xi'an, the capital of Shaanxi, locals would tell you without doubt that it's Yangrou Paomo. It is a bowl of lamb soup served with hard flour “bread”, which is broken up and added to the soup. The soup is topped with slices of mutton, scallion(葱) and coriander(香菜). Then it is usually eaten with picked sweet garlic.

Soup Dumpling, Kaifeng

    A popular snack in Kaifeng, Henan, the dish is made up of three things: skin, meat and soup. The skin is made from flour, while the filling is usually pork. And just as its name suggests, the soup dumplings are filled with tasty soup. But how does the steaming hot soup get into the dumplings? It's actually been cooled and cut into cubes, which fit easily into the dough(面团). Along with the pork, the cubes become liquid soup once they're steamed.

Smelly Mandarin Fish, Huangshan

    Despite its name, Smelly Mandarin Fish(臭鳜鱼) is known for its good taste. A lot of travelers who visit Huangshan in Anhui want to taste it because they have heard of its reputation. Once the skin has been removed, the fresh is preserved in salty water for six to seven days, then fried and cooked in soy sauce. Although salting gives the fish its special smell, the original tender flesh is preserved well and given a delicious and unique taste.

Buddha Jumps Over the Wall, Fuzhou

    The dish has enjoyed an over 100-year-long worldwide reputation since it was invented in Fuzhou, Fujian in the late Qing Dynasty(1644-1911). Fotiaoqiang, or Buddha Jumps Over the Wall, got its interesting name from a poem a customer wrote. The poem said the dish was so delicious that upon smelling it, monks in the neighboring temple would jump over the wall to come and get some. Buddha Jumps Over the Wall is made up of many ingredients, including sea cucumber(海参), chicken, pork and mushroom. Because of these ingredients, it tastes extremely delicious while being highly nutritious at the same time.