英语语法分析

They are just as sane as the Principia, if their whole matter and purpose were not magical.

如果它们的内容和目的不是魔法性的，其智慧可以同《原理》相比。

After the publication of the Principia there is a complete change in his habit and way of life.

《原理》出版后，在他的习惯和生活方式中有了一个彻底的改变。

And so he continued for some twenty-five years, in 1687, when he was forty-five years old, the Principia was published.

而他就如此持续奋斗了大约25年。1687年，当他45岁时，《原理》出版了。