Complex sentence: The brain drain has invariably led to the creation of two social classes--the bourgeoisie and the proletariat, this distinction has come to exist when looking at skilled labourer's vs unskilled labourers.
Split into simpler sentences: The brain drain has invariably led to the creation of two social classes--the Bourgeoisie and the Proletariat. This distinction has come to exist when looking at skilled labourers vs unskilled labourers.