加粗的地方有些疑问。。麻烦好心人解答一下~

The quantity of deposits that banks can create is limited by three factors:
1。The monetary base：
The size of the monetary base limits the total quantity of money that the banking system can create because
①Banks have desired reserves
②Households and firms have desired currency holdings

And both of these desired holdings of monetary base depend on the quantity of money.
这里不太懂为什么货币量增加，人们的持有现金和银行持有储蓄的欲望会增加。。是有具体原因还是只是个大趋势？

2。 Desired reserves略

3。 Desired currency holding
We hold money in the form of currency and bank deposits and some fraction of their money as currency.
So when the total quantity of money increases, so does the quantity of currency that people want to hold.
Because desired currency holding increases when deposits increase, currency leaves the banks when they make loans and increase deposits.
这里不太明白loan不应该是reserve的一部分吗，loan以currency形式流出了那么deposit不是不变吗，我一直理解的是loan+reserve是银行的asset，deposit是liabilities。。完全糊涂了，求救啊大半夜的


This leakage of currency is called the currency drain.
The ratio of currency to deposits is called the currency drain ratio.