来自《耶鲁大学开放课程：金融理论 第7集 第7集》

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  so it takes a second to adjust to it,
  需要一点时间去适应
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  but there's no cleverness involved in figuring these out.
  但是并不需要很聪明才能弄明白这些知识
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  Now, so we've got the doubling rule, we've got coupon bonds,
  现在我们讲了翻倍法则和息票债券
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  so that's simple.
  这些都很简单
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  Now, somewhat subtler thing is an annuity.
  年金的问题有点难度
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  So an annuity pays you a fixed amount for a fixed number of years.
  年金指一定的年限中每年支付固定的金额
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  So it doesn't pay the principal at the end, so it pays that C.
  它不在最后还本 而是每年支付金额C
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  That's supposed to be a capital C.
  记为大写字母C
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  It pays C, C, C, C for a fixed number of years.
  直到期满前每年都支付固定金额C
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  So it's a T period annuity.
  这是一个T时期的年金
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  Now annuities also can be changed in two important ways.
  年金有两种重要的分类
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  They can be indexed to inflation.
  有修正通货膨胀的