请问immediate annuity和deferred annuity的区别

它们两个的区别主要是现金流的收付时间不同。immediate annuity支付的现金流发生在现在，收到的现金流可能从现在可以，也可能从未来开始，而deferred annuity是未来收付现金流的。支付和收到的现金流往往是从未来开始。因此，

immediate annuity支付的现金流发生在现在，而deferred annuity是未来支付现金流的。

这是原版书的定义：With an immediate annuity, an amount of money is paid to the insurance company in return for a guarantee of specified future monthly payments over a specified period of time, either a number of years or the life of the insured, who is called the annuitant. A deferred annuity allows an individual to purchase an income stream to begin at a later date.