Because usually it doesn't work. And so one of the things that I think is very important is to always begin by testing each unit.

因此我认为非常重要的一件事情,就是开始测试的时候先对,每个独立单元进行测试。

麻省理工公开课 - 计算机科学及编程导论课程节选

and going to get the Christmas tree was always really a big deal in my house.

装饰圣诞树一直是我们家的一件非常重要的事情。

洛克菲勒中心的时光 - SpeakingMax英语口语达人