I was trying to explain to a friend why something is happening and they just couldn't get it. I don't get why they couldn't understand me. 
ohh, what did you try to explain them?
I was trying to explain to them why the Great Recession was caused by the recycling of petrodollars and an unrestrained financial market. 
Ohh, sometimes people don't understand simple things. I think the words like 'petrodollars' might have confused them.