1. Man is a rational being.
    人是有理性的生物.

2. It may also be said that rational, industrious, useful human beings are divided into two classes:
    也可以这样说，理智的，勤劳的、有用的人可以分为两类：

3. Where the raising of children and the investment of both parents in the children's lives were guaranteed by bonds of friendship between the parents, which were based on rational love.
    在这样的家庭里，父母间由于理性的爱所带来的友好关系保证了他们能共同抚养孩子和共同在孩子身上投入。

4. It's important to stay rational.
    重要的是保持理性。

5. Fortunately, there is a ´uniquely rational way´ for us to communicate with other intelligent beings,
    幸运的是，有一种我们可以和其他智力生命通迅联系的"唯一合理的方法"，