He used to be a slow learner. When he turned 15 he suddenly was enlightened and became a quick learner.

他本来学习很慢，但是一过15岁以后突然开窍，学习快了起来。

youdao

He used to be a slow learner. When he turned 15 he suddenly was enlightened and became a quick learner.

他本来学习很慢，但是一过15岁以后突然开窍，学习快了起来。

youdao