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问题 选择题

小明在探究蔗糖的性质实验前，所做的假设属于化学变化范畴的是

A．能否溶于酒精

B．能否磨碎变成糖粉

C．能否变成酒精

D．能否通过结晶方法变成大晶体

答案

答案：C

题目分析：ABD三个假设都没有生成其他物质，能否变成酒精生成了新的物质属于化学变化。

单项选择题

On May 29, 1973, Thomas Bradley, a black man, was elected mayor of Los Angeles. Los Angeles is the third largest city in the United States, with a population of three million. About sixteen percent of the city’s population are black.
News of this election appeared on the front pages of newspapers everywhere in the United States. Here is how one major newspaper reported the event.
LOS ANGELES ELECTS BRADLEY MAYOR UNSEATING YORTYBLACK WINS 56% OF VOTES
Bradley called his victory over Yorty "the fulfillment of a dream". During his childhood and youth, people had kept telling him, "You can’t do this, you can’t go there, because you are a Negro. " Nevertheless he had won a decisive victory over a man who had been won 43.7 percent.
Los Angeles voters have had many opportunities to judge. Thomas Bradley had to form an opinion of him. The son of a poor farmer Texas, he joined the Los Angeles police force in 1940. During his twenty-one years on the police force he earned a law degree by attending school at night. He was elected to the city council ten years ago.
At the time of the Los Angeles election, three other American cities already had black mayors, but none of those cities had as large a population as Los Angeles. Besides, the percentage of blacks in those other cities was much larger. Cleveland, Ohio, had thirty-six percent black when Carl Stokes was elected mayor of Cleveland in 1967. In the same year Richard Hatcher was elected mayor of Cary. In Newark, New Jersey, sixty percent of the population were black when Kenneth Gibson was elected in 1970. Thus election of a black mayor in those cities was not very surprising.
In Los Angeles thousands of white citizens voted for Thomas Bradley because they believed he would be a better mayor than the white candidate. Bradley had spent forty-eight of his fifty-five years in Los Angeles. Four years ago Bradley lost mayoral election to Yorty. This time Bradley won.

Bradley hit the front page headline for ______.

A. he was the first black mayor in history
B. he was the first black mayor in the south of the USA
C. he was the first black mayor of one of the largest cities in the USA
D. a poor farmer’s son could also win an important election
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单项选择题

吐痰清稀色白者，属（）

A.寒痰

B.湿痰

C.风痰

D.燥痰

E.热痰
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