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问题 单项选择题

空间环境噪声测试时，应注意声级计的档位应在（）位置。

A.A计权

B.B计权

C.C计权

D.D计权

答案

参考答案：A

解答题

已知关于x的方程x2+3x-m=0的两个实数根的平方和等于11．求证：关于x的方程（k-3）x2+kmx-m2+6m-4=0有实数根．
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补全对话，情景问答
根据对话内容，用方框中所给词的适当形式填空。
Family,  too,   do,   five,  and,  farmer,  like
( At an English corner)
A: Hello! I'm Peter.
B: Hello! I'm Liu Dong. Nice to meet you.
A: Nice to meet you, 1__________
B: I'm from China. Where're you from?
A: I'm from America. How many people are there in your 2__________?
B: There' re 3__________. They' re my grandpa, grandma, father, mother and I.
A: What do your parents 4__________?
B: My father's a teacher 5__________ my mother works in a bookstore.
A: Does your father 6__________ his job?
B: Sure. He likes teaching very much. What about your parents?
A: Both of them are 7__________. They have a big farm.
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