learning是什么时态

　　This research has done much to advance our understanding of language learning.

　　这项研究大大提高了我们对语言学习的认识。

　　A good dictionary is indispensable for learning a foreign language.

　　一本好词典是学习外语必备的。

　　The children are learning to understand people of different faiths.

　　孩子们在学习理解不同宗教信仰的人。

　　Last season was a learning experience for me.

　　上个季度对我来说是一次学习。

　　Reading is of vital importance in language learning.

　　阅读在语言学习中至关重要。