应该是只剩下银币，可以假设市场比价是指国外的比价哦，那么都会争先用银币到官方换金币，再将换到的金币运到国外换取银币后运回国内，久而久之，国内只剩下银币，金币则全部运到国外了...这是一种理解，而且比较通熟易懂的

从wiki上查到一段话，从流通的角度举了个例子
Gresham's Law comes into play, when several types of money have a conversion ratio specified by legal tender laws, different from their market price.

For example, let's say the law sets the ratio at 20 ounces of silver for one ounce of gold; but the market price of gold is only 15 ounces of silver. Any contract or debt in silver can be now paid in gold. So instead of expending 20 silver, the debtor will buy an ounce of gold for 15 ounces of silver. As a result, no one will be willing to enter a contract quoted in silver.

The undervalued money will vanish from the market, bringing down prices quoted in it. Those still using it will likely find themselves in trouble, because they made debts and investments under the old price level and expected their incomes to be correspondingly higher. The 'good money' will be held by the users of money, or sold into other countries, where the local laws do not apply. This exchange of currencies takes time, while the supply of money shrinks. This produces a temporary deflationary effect.[1]

The Law is a special case of the usual effects of price controls by government: in this case, the government’s artificial fixing of an exchange rate between two or more moneys creates a shortage of the artificially under-valued money and a surplus of the over-valued money.[2]

我自己编了个小故事，帮助自己理解记忆。

假设金币和银币的法定比价是1:13，市场比价也是1:13。

有些人（更多的是zf）发现银币的掺假难度和掺假成本比价低，于是将银币熔化之后掺入铜、锡等金属，重新铸造成银币；或者从银币上刮一点银粉下来，将银粉铸造成银币；原来的13个银币变成了现在的15个银币。

随着含银量偏低的银币（劣币）的增多，人们发现银币的含银量降低，于是市场比价变为了1:15，而法定比价没有变。

金币因不易掺假，保值功能（财富贮藏）很强，人们将金币藏在自己家里，而在日常的经济活动中尽量使用银币，于是流通中的金币越来越少（金币退出流通），流通中的银币越来越多。