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 English tenses are not always easy to translate into Arabic. An overview of all English tenses and moods and how to express them in Arabic.
After an Egypt Air flight crashed in 1999 at JFK airport, the US investigators stiffened on the last words of the flight officer: "tawakkaltu ala Allah"
قط (qattu) can denote "never" in the Past. What about the word أبدا (abadan)? It is only for the future.
The verb ba'a (بَقى) in Egyptian Arabic is tricky. You'll hear this verb in many situations. In general, it is used with a following past tense verb.
The Arabic word إذا (idha) is very tricky. Sometimes it is written without an Aleph - the spelling matters.