21.   As a result, refiners raced to replenish their lean inventories to have enough supply, driving prices higher.

22.   As demand grows, the scarcity could drive prices higher.

23.   As Greenspan suggested, the Fed is concerned that giddy investors are driving share prices to unjustified levels on the basis of false assumptions.

24.   As demand drives the price of the bond higher it also drives up the price of the futures contract for which it can be delivered.

25.   As weather and stockpile concerns drove futures prices higher earlier this year , retail prices followed suit.

26.   As supply has increased, driving prices down, more-addictive heroin has increasingly replaced weaker opium as the drug of choice.

27.   Because the stock trades so thinly, a wave of investors trying to swap their holdings could easily drive the price down.

28.   Because investors have shunned gold for the past few years, adding even small gold allocations to their portfolios could be enough to drive prices higher still.

29.   Because most investors have bought stocks on a bet that those conditions will persist, fuel to drive prices even higher may be in short supply.

30.   Bond yields increase in the face of inflation, driving prices in the opposite direction.