Something that takes two inputs, a left operant - and a right operant and it just returns a Boolean value is-- or rather it returns a left to right value.

它有两个输入，一个是左边的作用物,一个是右边的作用物，然后返回一个布尔值-,或者更确切地说，返回一个从左到右的值。

哈佛公开课 - 计算机科学课程节选

Back in the 1840s, life insurance was very important because the average expectancy of life was only something like forty-five years, so that meant parents were dying left and right.

在19世纪40年代的时候,寿险是非常重要的,因为当时的人均期望寿命,仅为45岁左右,这意味着双亲平均只能活到45岁

耶鲁公开课 - 金融市场课程节选