你需要的第一件东西就是一套有声语言教材。

The first thing you need is an audio language course.

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你可能会考虑你现在使用的英语语言教材是你过去经常使用的选择标准。

You might also like to think about the criteria that you used to select the ELT materials that you are using at the moment.

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然而各种华语作为第二语言教材缺乏明确统一的水平等级标准作为编写参考。

However, there is a lack of a uniform compilation standard for such teaching materials.

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