Without successful arguments, we can't deny the existence of the language.

论证的不成功并不能够否定语言存在。

youdao

Could we ever teach a foreign language without published materials?

我们有过曾不使用出版教材来教一门外语吗？

youdao

Could we ever teach a foreign language without published materials?

我们有过曾不使用出版教材来教一门外语吗？

youdao