Questions & Answers about عندما تكون أمي جاهزة، نخرج من البيت ونذهب إلى السوق.
عندما means when.
In this sentence, it introduces a time clause:
- عندما تكون أمي جاهزة = when my mother is ready
After that, the main action follows:
- نخرج من البيت ونذهب إلى السوق = we leave the house and go to the market
So the sentence structure is:
- When X happens, Y happens.
This is a very common way to connect events in Modern Standard Arabic.
That is a very common question.
It is true that in simple present-tense sentences, Arabic often omits to be. For example:
- أمي جاهزة = My mother is ready
There is no separate word for is there.
But in this sentence, Arabic uses تكون because the clause is introduced by عندما and refers to a situation like when my mother is ready. In this kind of time clause, using a form of كان / يكون is very natural.
So:
- أمي جاهزة = My mother is ready
- عندما تكون أمي جاهزة = When my mother is ready
Here, تكون is the feminine singular form of to be / become in the present tense.