It had become free territory under the Missouri Compromise.

VOA: special.2009.05.14

It was then in a matter of moments, that I decided that I had to find out why and become happier.

也就是在那时，我决定要找出原因，变得快乐。

哈佛公开课 - 幸福课课程节选

It had become a struggle for human freedom.

VOA: special.2009.10.15

Lee soon discovered that it would not be easy to break out of the trap that Richmond and Petersburg had become.

VOA: special.2009.12.17

It was true. Giovanni had become very thin.

VOA: special.2009.05.23