1.   Some researchers have speculated that some mechanism lets hungry animals store more of the fat they eat when they gorge than when they nibble more regularly.

2.   This mechanism lets the central bank boost its reserves without driving down the value of the peso.

3.   Opponents say such a mechanism would let Washington paper over any real work to cut pollution.

4.   Opponents say such a mechanism would let Washington avoid its pollution-cutting obligations.

5.   Under EU rules, the EMS exchange rate mechanism lets currencies fluctuate against each other.