China buys Treasuries because they suit its currency policy and the export-led growth that it has relied on over the past 33 years. As a surplus saver, China has run large current-account surpluses since 1994, accumulating a massive portfolio of foreign-exchange reserves that now stands at almost $3.7 trillion.
中国之所以购买美债是因为这符合其货币政策以及33年以来一直依赖的出口导向型增长。作为一个贸易盈余的储蓄者，中国自1994年以来就拥有大幅经常账户盈余，并逐渐积累到今天将近3.7万亿美元的巨额外汇储备。