NO.PZ2016010802000219
问题如下：
A country with a persistent trade surplus is being pressured to let its currency appreciate. Which of the following best describes the adjustment that must occur if currency appreciation is to be effective in reducing the trade surplus?
选项：
A.Domestic investment must decline relative to saving.
B.Foreigners must increase investment relative to saving.
C.Global capital flows must shift toward the domestic market.
解释：
C is correct.
The trade surplus cannot decline unless the capital account deficit also declines. Regardless of the mix of assets bought and sold, foreigners must buy more assets from (or sell fewer assets to) domestic issuers/investors.
考点：The Trade Balance
解析：经常性账户和资本账户是此消彼长的两个账户。
经常账户与资本平衡。经常性账户盈余的消失那么资本账户赤字也必须消失，这就代表外资流入。C选项正确。
依据公式（X-M）=(S-I)+(T-G)。
投资I减小，等式右边变大，左边也会相应变大，经常性账户盈余还会增加，A选项错误。
外国人要增加对于经常性账户赤字出口国的投资才行。外国人只投资自己国家不解决问题，所以B选项错误。
为什么current account 和 capital account 会此消彼长？麻烦解释一下
