If you're learning Arabic (and unless you were raised speaking it, you're never done!), then you've grappled with the enormously difficult system of the Forms (Measures) of the Arabic Verb.
Setting aside the question of the irregular verbs, even the most regular of letters can have up to ten different forms in which to appear.
As a handy reference, here is a presentation the 10 main Arabic Verb Forms. (There are a few extremely rare and now archaic and unused Forms beyond the 10. Don't worry about those.)
While you're just getting started in Arabic, it's important to have a clear chart of the Arabic Verb Forms readily on hand to consult while you're needing to look things up in your dictionary.
The best one I've seen for casual learning purposes are available for sale on the internet by one Snarla Husayn.
She has her chart of Arabic Verb Forms available in the form of a mousepad:
A wall poster:
And even a t-shirt with the Arabic Verb Forms!:
As long as you're buying nifty Arabic learning materials, check out Snarla Husayn's Store at Zazzle, where she has, among other things--
Shaykh Zubayr (get it, Shakespeare in a kafiyah!):
Anyway, what I found while learning Arabic is that the more I surrounded myself with the language constantly, the greater progress I made. And products like these really can help make the language come alive.