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Can't see what is with بسب و لان . :/

بسب
bi-sab : reason
لان
li-an-na : because

i hope it helps:

بسبب reason -because of
لأن because -

Sorry, I meant to make this an answer not a comment!!

Also, بسبب can be followed only by a nominal sentence الجملة الإسمية, not a verbal one الجملة الفعلية. On the other hand, لان can be used with both verbal and nominal sentences. Also, keep in mind it is "bi-sab-ab", بسبب not "bi-sab" بسب which is what you've written above. You might be interested to know that it comes from the word 'reason' سبب and literally means something like 'for the reason'. In other words, it is the word سبب + the preposition ب. In conclusion, you could use بسبب like this: لا أريد أن أذهب إلى الشاطئ بسبب الطقس I don't want to go to the beach today because of the weather. You could also use لان here as well. If you have any more questions, feel free to message me.

بسبب is used for reasoning actions that happened/or did not happen in the past.
لم اذهب الى الشاطيء بسبب رداءة الطقس
لا اريد الذهاب للشاطيء لأن الطقس سيء