Learn Hardcore Arabic (Modern Standard): لو كان الحليب في الثلاجة، لصنعت أمي قهوة لنا. - If the milk were in the refrigerator, my mother would make coffee for us.

لو usually introduces a counterfactual or unreal condition in MSA Arabic. It often corresponds to English if ... were / had ... would ....

So in this sentence, لو كان الحليب في الثلاجة، لصنعت أمي قهوة لنا suggests that the milk is not in the fridge, and therefore the coffee was not made.

This is different from a more open, real possibility, where Arabic might use إذا or sometimes إن instead.

Why is كان used here? The sentence is about a hypothetical situation, not the past.

That is a very common question. In Arabic, after لو for unreal conditions, the verb is often put in the past form, even when the meaning in English is closer to were or would be rather than a simple past.

So:

لو كان الحليب في الثلاجة literally looks like if the milk was in the fridge
but the real meaning is if the milk were in the fridge

This is a normal Arabic pattern. The past form here does not simply mean past time; it helps express an unreal or contrary-to-fact condition.

Why is it كان and not كانت?

Because الحليب is a masculine singular noun.

The verb كان agrees with its subject in gender and number, so: