His gift carried one condition. He said La Brea could only be used for scientific work.

VOA: special.2010.04.07

I will only do them on one condition, and that is I want to be able to teach you what the assumptions are that underlie the points in the derivation.

只在一个情况下我才会做，那就是要能够教会你们,假设是,构成了推导的基础。

麻省理工公开课 - 固态化学导论课程节选

In one condition you're the only person around.

情景一是你单独一人。

耶鲁公开课 - 心理学导论课程节选