In principle, a currency adjusts to keep economies in balance, but in practice, argued Mr Mundell, exchange rates veer wildly from their ideal levels.
原则上，调整汇率可以保持经济平衡，但是汇率，孟德尔先生争论说，实际上大大偏离了它们的理想水平。
2
Principle 3 You should always try to know the level of instability of the given pairs of currency .
原则3应经常设法了解你的水平双双获得货币的不稳定。
3
In principle, a joint venture shall adopt Renmibi as the standard currency for accounting. It may also adopt a foreign currency for the same purpose upon agreement by the parties to the joint venture.