In this case, I'm going to get back the answer 3 F-O-O because the user typed in F-O-O, but wait a minute, what's with this?

假若这样，我得到了答案3,因为用户输入了，等一下，用这个干吗？

哈佛公开课 - 计算机科学课程节选

This refers--this actually goes back to B.F. Skinner, a psychologist who flourished in the first half of this century.

这要追溯到B.F.斯金纳,一位活跃在上世纪前期的心理学家

耶鲁公开课 - 金融市场课程节选