Complex sentence: The Central Committee did this because the majority of its members were of provincial background, or were working in the provinces; because of this, these members were the first to feel the pinch when the economy began to stagnate during Lê Khả Phiêu's rule.
Split into simpler sentences: The Central Committee did this because most of its members had a provincial background, or were working in the provinces. These members were the first to be affected when the economy began to stagnate during Lê Khả Phiêu's rule.