Supreme Court Justice Sandra Day O' Connor is in her 70s and former surgeon general C. Everett Koop chairs an Internet start-up in his 80s.

最高法院法官 Sandra Day O' Connor 已经70多岁，前卫生局局长 C. Everett Koop 在80多岁时还担任一个新成立的互联网公司的主席。

youdao

This experiment is to start at 3 o 'clock.

实验3点钟开始。

youdao

They start school at 9 o 'clock. School is fun here. I like it.

他们学校是9点开始上课。这里的学校很有趣。我喜欢。

youdao

You start with O double minus, so that is oxygen plus two electrons.

你从氧二负离子，也就是氯元素带2个负电子。

麻省理工公开课 - 固态化学导论课程节选