貌似可行，就是怕个别年份的大通胀
We sell Treasury Bonds for a term of either 20 or 30 years.
Bonds pay a fixed rate of interest every six months until they mature.
You can hold a bond until it matures or sell it before it matures.

30年利率现在是4.75%
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修改:Flip FROM 98.4.43.*
FROM 98.4.43.*