لو (lau) means if. But it has a more specific use than the English word "if". لو (lau) is used for events that didn't happen. For example if the following sentence were translated into Arabic with the word لو (lau) as a translation for the word "if":
If I had been trained, I wouldn't have made mistakes.
Then a person who read the translation, understands that the person saying the sentence was NOT trained. Using لو (lau) makes sure this doesn't happen.
Speaker 1: If I were stupid, then...
Listener 1: Were you stupid?
The "then" word for لو is لـ . It is added to the beginning of the word.
- لو ..1..لـ ...2...ـ
if ...1.... then ...2....
example: If I didn't go to school, my mom would get angry (but I did go to school).
- لم أهزمهم
(I) hadn't beaten them.
- لو لم أهزمهم لكانو هزموني
lau lam ahzim-hum la-kaanoo hazamoo-nee
If I didn't beat them up they would beat me up. (assuming the speaker did "beat them up")