南成中学八年级学生参加身体素质测试，数据如下：优秀良好及格不_爱下问搜题

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问题解答题

南成中学八年级学生参加身体素质测试，数据如下：

优秀	良好	及格	不及格
51人	156人	81人	21人

根据以上信息，补全下面统计表．

分组	频数	频率（精确到0.001）
优秀
良好
及格
不及格
合计

答案

总人数=51+156+81+21=309，

优秀的频率=51÷309=0.165；

良好的频率=0.505；

及格的频率=0.262；

不及格的频率0.068．

如图：

分组	频数	频率（精确到0.001）
优秀	51	0.156
良好	156	0.505
及格	81	0.262
不及格	21	0.068
合计	309	1

完形填空

One night, Mary heard some big 36_ noise. “Doh, Doh, …” It 37  for a few minutes. Mary went out of her bedroom to search everywhere. Her parents were sleeping and there were no  38 people in the house. Mary   39 _ to her bedroom.
Mary heard the noise again. She thought, “Is it a cat? Mike has a cat. But cats miaow. They don’t make such noise.”
“Maybe it’s a bird   40  around and looking for a place to rest. No! That doesn’t make any noise.”
Maybe it’s the whisper of my parents. They _41  be   42  in their room. But that noise wasn’t a whisper at all.”
Mary went to bed again but she heard the noise again. She was   43_   and fell 44_   her bed. Her legs were   45_   and she could not climb up any more.

A．frightening

单项选择题 A1/A2型题

能参与蛋白质合成场所结构的核酸是（）

A.tRNA

B.mRNA

C.rRNA

D.hnRNA

E.DNA