题干

小明在帮妈妈洗碗时,发现同一只碗有时可以漂浮在水面上,有时也可以沉入水底,如图所示,请你分析下列说法正确的是(  )

A:碗沉入水底时比漂浮时排开水的质量减小了

B:碗沉入水底时受到的浮力等于它的重力

C:碗沉入水底时比漂浮时所受的浮力变大了

D:碗沉人水底时比漂浮时所受的重力变大了

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A

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    Every people uses its own special word to show its ideas and feelings. Some of these expressions(表达,说法) are commonly used for many years. Others are popular for just a short time. One such American expression is “Where's the beef?” It is used when something is not as good as it is said to be. In the early 1980s “Where's the beef?” was one of the most popular expressions in the United States. It seemed as if everyone using it at the time.

    Beef, of course, is the meat from a cow, and food is more popular in America than a hamburger made from beef. In the 1960s a businessman named Ray began building small restaurants that sold hamburgers at a low price. Ray called this “McDonald's”. Ray became one of the richest businessmen at last in America.

    Other business people watched his success. Some of them opened their own hamburger restaurants. One company called “Wendy's” said its hamburgers were bigger than those sold by McDonald's or anyone else. The Wendy's Company began to use the expression “Where's the beef?” to make people know that Wendy's hamburgers were the biggest. The Wendy's television advertisement showed three old women eating hamburgers. The bread that covered the meat was very big, but inside there was only a bit of meat. One of the women said she would not eat a hamburger with such a little piece of beef. “Where's the beef?” she shouted in a funny way. The advertisement for Wendy's hamburger restaurants was success. As we said, it seemed everyone began using the expression “Where's the beef?”.