A formidable obstacle or a tough challenge that is difficult to overcome.
学习一门新语言，发音往往是许多人的一个硬门槛子
When learning a new language, pronunciation often serves as a formidable obstacle for many people.
Era:
Modern
Frequency:
Next Idiom
A formidable obstacle or a tough challenge that is difficult to overcome.
Era:
Modern
Frequency: