Therefore, th e author suggests that foreign language teachers should pay attention to how to help learners to improve language proficiency before fossilization occurs.

• 因此如何使学习者在高原期及高峰期到来之前,最大程度地掌握外语知识,提高外语能力,以及如何在石化后减少回退的程度,应引起外语教学研究者及外语教师的重视。