sentence1: but uh but they don't require a lot if the only the problem that i've seen in the past is like when you've got uh if you've got natural gas and heat of course you don't in the east i suppose you don't have a lot of natural gas heat but if you don't have your y our heat adjusted your gas adjusted right then you can get some stains you know on the ceilings and you know ceiling ceiling
sentence2: The stains on the ceilings are caused by natural gas and heat.