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【简答题】
一观察者静止于铁轨旁 , 测量运行中的火车汽笛的频率.若测得火车开来时的频率为 2010 Hz, 离去时的频率为 1990 Hz, 已知空气中的声速为 330 m.s -1 , 则汽笛实际频率 n 是 .
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举一反三
【多选题】土地改革后，小农经在发展中暴露出来的问题有（ ）。
A.
难以避免两极分化的出现
B.
难以应对自然灾害的影响
C.
难以进行大规模的农田水利建设
D.
难以进行分工和协作
【单选题】Passage 4 Questions 16 to 20 are based on the following passage: Animals seem to have the sense to eat when they are hungry and they do not eat more than their bodies need. It has been demonstrated th...
A.
encourage rats to drink vitamin-enriched water
B.
find out rats preference in flavor
C.
test whether rats know which drink is good for them
D.
demonstrate that vitamins are tasteless
【简答题】书本P42页业务47,请写出摘要及会计分录(将题目中的应收票据改为应收账款来做,总金额为1193400)
【单选题】Passage 4 Questions 16 to 20 are based on the following passage: Movies are the most popular form. of entertainment for millions of Americans. They, go to the movies to escape their normal everyday ex...
A.
to enjoy a good story
B.
to experience an exciting life
C.
to see the actors and actresses
D.
to escape their daily life
【单选题】Passage 4 Questions 16 to 20 are based on the following passage: Animals seem to have the sense to eat when they are hungry and they do not eat more than their bodies need. It has been demonstrated th...
A.
encourage rats to drink vitamin-enriched water
B.
find out rats preference in flavor
C.
test whether rats know which drink is good for them
D.
demonstrate that vitamins are tasteless
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