现在，也许历史上第一次出现了一种——英语。

Now, for the first time in history, perhaps there is one—English.

youdao

米莉在体育课上第一次笑了。

Millie smiled for the first time ever in gym class.

youdao

这个无名人士让人类的发展跨出了历史性的一步，因为正是在那一年，人类在其历史上第一次成为主要的城市物种。

This nameless person pushed the human race over a historic threshold, for it was in that year that mankind became, for the first time in its history, a predominantly urban species.

youdao

So now, the enzyme is locked up with being built, and the penicillin has effectively killed the bacteria.

所以这是我第一次感受到,我想在单个原子的层面上思考这些分子,所以这时我的专业转到了化学方向。

麻省理工公开课 - 化学原理课程节选

You have to be comfy on camera but this is your first chance to say hello to mom and dad on camera.

在镜头前表现得自然点儿,因为这是你第一次在电视上跟爸妈打招呼。

哈佛公开课 - 计算机科学课程节选

The bill was passed, and within five months after the bill was passed, we had double digit unemployment for the first time.

法案顺利通过，法案通过后五个月，失业率就达到了两位数,是史上第一次。

斯坦福公开课 - 经济学课程节选