Refined sugar futures fell $91.50, or 12%, to close at $677.10 a metric ton Commodity stocks to watch: --Aluminum producer Alcoa ( AA ) fell sharply over concern--like many other commodities stocks--that China would pull back spending on raw materials. Fears that the Chinese government will raise interest rates to rein in inflation pushed crude-oil futures sharply into the red to finish the week. In other energy futures, heating oil was down 2.46% to $2.36 a gallon while natural gas fell 3.08%, to $3.80 per million British thermal units.