It is the duty of every citizen to make the country rich and powerful (To make the country rich and strong is...).

使国家富强是每个公民的责任（要使国家富强是……）。
In order to accomplish this object one must be patriotic (love his country).
为了达到此目的，必须爱国。
I consider this an unchangeable truth.

我认为这是一条不易的定理。

How can a student love his country (be patriotic)? I find my answer very simple and clear.
一个学生如何才能爱国呢？我发觉答复很简单明了。
He must study hard and store up knowledge so as to serve his (the) country in the future.
他必须用功读书并积储知识以便将来服务国家。
If every student can do according to what I said, the country will certainly be rich and powerful.

如果每个学生能按照我所说的去做，国家一定会富强。