Deborah Withington of Sound Alert says that the alarms use most of the frequencies that can be heard by humans.

该公司的戴博拉·威星顿称此种警报器使用人类可以听到的部分音频。

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Deborah Withington of Sound Alert says that the alarms use most of the frequencies that can be heard by humans.

该公司的戴博拉·威星顿称此种警报器使用人类可以听到的部分音频。

youdao