The dollar finished the day slightly down.
当日结束时美元汇率略有下降。
What's the rate of exchange against the dollar?
与美元的兑换率是多少？
Here's a five dollar bill ─ please keep the change.
这是一张五元的钞票——零钱就不用找了。
If you want the best, you have to pay top dollar.
你想要最好的，就得花大钱。
The US dollar went through a difficult time, in company with the oil market.
美元与石油市场同时经历了艰难时期。