法国大革命开始和结束的事件分别是(     )

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    New Orleans, Louisiana, was established as part of the French Empire in 1718.

    Its location on the east bank of the Mississippi River gave it control of the American hinerland and it became strategically important to many nations. It was transferred from France to Spain, returned to France, and finally sold by Napoleon to the United States in 1803. The city was the site of a famous battle fought in 1815 between the British, who hoped to control it, and the Americans under General Andrew Jackson.

    The riverbed of the Mississippi is constantly silting（淤积）and the river is now actually higher than the city. Levees hold back the river and giant pumps are used to move water from the city into the river.

    Although New Orleans has been a part of the United States for almost two centuries, its population takes great pride in its French heritage. Louisiana still retains parts of the Code Napoleon which, for many years, was its only law.

    New Orleans is carefree city and it boasts its hot, spicy Creole seafood and its native Dixieland Jazz. The Jackson Square neighborhood maintains its French colonial homes and in other sections are pre-Civil War mansions. Visitors are surprised to find that behind this interesting surface of yesteryear is a busy industrial and port city. Grain and coal come from the Midwest and foreign goods are unloaded here. New Orleans is no longer a sleepy Southern town—but it's still fun to visit.

碱石灰是NaOH与CaO的混合物，取一定量露置于空气中部分变质的碱石灰，加水充分搅拌后过滤，所得物质成分可能是(     )