All the energies are negative because it is a bound system. I start up here with n equals one.

所有能量级都是负数，因为它是一个束缚系统,在这里我从n等于1讲起。

麻省理工公开课 - 固态化学导论课程节选

Or you get a cold, the cold virus takes hold, the viruses start replicating inside of you and it takes some time for immune system to gear up to eliminate it, so we're used to thinking about responses that take some time.

或者你得了感冒,感冒病毒扎根在你的身体中,病毒开始在你体内复制,免疫系统需要一定时间做好准备去消灭它,所以我们曾认为免疫反应需要一定时间

耶鲁公开课 - 生物医学工程探索课程节选