Complex sentence: First, a large number of the locals had been paid comparatively well and had learned basic conversational English; this made them more marketable to the outside world, and a significant number of them now work in the Middle East oilfields.
Split into simpler sentences: First, a large number of locals had been paid comparatively well and had learned basic conversational English. This made them more marketable to the outside world, and a significant number went to work in Middle East oilfields.