很多外语种学生在单词重音和语调方面存在学习难题，也就是对人们说话时的声音的升高和降低把握不准。

Many students of a foreign language have trouble with word stress and intonation - raising and lowering the sound of your voice when you speak.

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在长官或长辈面前，说话的声音要降低。

When talking in front of our elders, we should lower our voice.

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