"Because" et "Because of"
Because = "parce que"
Because of = "à cause de"
Comparez:
she doesn't want because it is snowing!
Elle ne veut pas parce qu'il neige.
He didn't come because he was ill.
Il n'est pas venu parce qu'il était malade.
She doesn't want because of the snow.
Elle ne veut pas à cause de la neige.
He didn't come because of his illness.
Il n'est pas venu à cause de sa maladie.