5个相同的声压级迭加，总声级较单个增加（）分贝。 A.3 B.5 C.7 D.10_爱下问搜题

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问题单项选择题

5个相同的声压级迭加，总声级较单个增加（）分贝。

A.3

B.5

C.7

D.10

答案

参考答案：C

选择题

—I think Miss Gao must be in the library. She said she would go there.

—No, she ________ be there. I have just been there..

A. can't

B. mustn't

C. needn't

D. wouldn't

填空题

传统音韵学可以细分为四个部门：今音学、古音学、等韵学、（）。