The SION Rule (Major)

This Rule applies to those words in English that end with the letters

....sion

To translate them into Spanish, we will substitute the ending with

...sión

What's this?
This ought to be very easy!
It is! We write them exactly as they are in English!
Well, not exactly: remember the Quirks! Also, no double letters (GG, MM, NN, PP, SS or TT) and F instead of PH.
For example, the English word "compulsion" is the same in Spanish except that we accentuate the last syllable (it ends in "..ión") [see "Accents", Chapter One].
Here are some Examples

The SION Rule

English Spanish Helpful Reminders
...sion ...sión
Aspersion Aspersión
Compassion Compasión only 1 S
Comprehension Comprensión no H
Compulsion Compulsión
Conclusion Conclusión
Confusion Confusión
Decision Decisión
Defusion Defusión
Fission Fisión only 1 S
Fusion Fusión
Illusion Ilusión
Lesion Lesión
Mission Misión
Passion Pasión only 1 S
Pension Pensión
Seclusion Seclusión
Session Sesión only 1 S
Tension Tensión

Well, anyway, you get the idea.
We can skip the practice session.
(You already know how to write in English!)
Unfortunately, there aren't that many words in this Rule. Somewhat less than three hundred, perhaps.
But it counts; after all, it is Spanish!