Al-Jazeera offers a grammar test. There are a couple of pitfalls. So, reason enough to take a look at the most important Arabic grammar topics.
The correct vowel endings damma, kasra, fatha in Arabic can be a headache. If you are careless, you could turn verse 9:3 of the Qur'an into blasphemy (kufr).
9273 roots: 20 questions for the grammarian Antoine Robert el-Dahdah (الدحداح) who put Arabic grammar in charts and tables.
Before the Aleph or on top of it - the position of the Tanween fatha has long been debated. Egyptians and Syrians have different approaches
A final Aleph (ألف) in Arabic to express the accusative case (منصوب) can be tricky. Where do you put it on a final Hamza (همزة)? Here are the rules.
The word "me" can be the direct object of a verb (like in: help me!) - but this is not our story here. We talk about the word إِيّايَ.
In Arabic, you often use an "interpreted infinitive", a masdar muawwal - المصدر المؤول. This is formed by an أن plus verb in منصوب mood.