学习数学的唯一方法就是做数学。

I find I'm so excited. I can barely sit still or think about it. I think only those who have a long way to go on a journey to regain their freedom will feel the excitement of the upcoming mystery. I hope to cross the border and shake hands with my friends. I hope the Pacific is as blue as a dream. I hope。

We must design products with their end-of-life in mind from the very beginning.