可以讲一下S=I+（G-T）+（X-M）公式推导过程吗，谢谢

NO.PZ2016010802000217问题如下A country with a tra ficit will most likely:A.have offsetting capitaccount surplus.B.save enough to funits investment spenng.C.buy assets from foreigners to funthe imbalance.is correct.A tra ficit must exactly matcheoffsetting capitaccount surplus to funthe ficit. A capitaccount surplus reflects borrowing from foreigners (increase in mestic liabilities) anor selling assets to foreigners (a crease in mestic assets). A capitaccount surplus is often referreto a \"capitinflow\" because the net effeis foreign investment in the mestic economy.考点The Tra Balance解析当一个国家出现贸易逆差时，就表明该国进口了更多的商品，出口了较少的商品。资本账户和经常性账户具有此消彼长的关系。经常性账户出现赤字，那么资本账户就会出现盈余，所以A正确。X-M=S-I+(T-G)根据题意，X-M减少可以产生，S-I减少。这表明国内储蓄的钱不够，需要国外资金支援建设，所以B错误。C也说反了，应该是外国人买国内资产以维持平衡，而不是国人买外国资产维持平衡。 老师 我的思路是 这个国家出现了ficit 说明现在的X-M小 那就will most likely to raise （X-M） 所以要提升S或降低I或提升T或降低G。 所以我选了B 要提升saving。想问问这个思路为什么做错了。

NO.PZ2016010802000217 问题如下 A country with a tra ficit will most likely: A.have offsetting capitaccount surplus. B.save enough to funits investment spenng. C.buy assets from foreigners to funthe imbalance. is correct.A tra ficit must exactly matcheoffsetting capitaccount surplus to funthe ficit. A capitaccount surplus reflects borrowing from foreigners (increase in mestic liabilities) anor selling assets to foreigners (a crease in mestic assets). A capitaccount surplus is often referreto a \"capitinflow\" because the net effeis foreign investment in the mestic economy.考点The Tra Balance解析当一个国家出现贸易逆差时，就表明该国进口了更多的商品，出口了较少的商品。资本账户和经常性账户具有此消彼长的关系。经常性账户出现赤字，那么资本账户就会出现盈余，所以A正确。X-M=S-I+(T-G)根据题意，X-M减少可以产生，S-I减少。这表明国内储蓄的钱不够，需要国外资金支援建设，所以B错误。C也说反了，应该是外国人买国内资产以维持平衡，而不是国人买外国资产维持平衡。 资本账户可否理解为投资 I ？

NO.PZ2016010802000217问题如下A country with a tra ficit will most likely:A.have offsetting capitaccount surplus.B.save enough to funits investment spenng.C.buy assets from foreigners to funthe imbalance.is correct.A tra ficit must exactly matcheoffsetting capitaccount surplus to funthe ficit. A capitaccount surplus reflects borrowing from foreigners (increase in mestic liabilities) anor selling assets to foreigners (a crease in mestic assets). A capitaccount surplus is often referreto a \"capitinflow\" because the net effeis foreign investment in the mestic economy.考点The Tra Balance解析当一个国家出现贸易逆差时，就表明该国进口了更多的商品，出口了较少的商品。资本账户和经常性账户具有此消彼长的关系。经常性账户出现赤字，那么资本账户就会出现盈余，所以A正确。X-M=S-I+(T-G)根据题意，X-M减少可以产生，S-I减少。这表明国内储蓄的钱不够，需要国外资金支援建设，所以B错误。C也说反了，应该是外国人买国内资产以维持平衡，而不是国人买外国资产维持平衡。 请B为什么不对

NO.PZ2016010802000217 问题如下 A country with a tra ficit will most likely: A.have offsetting capitaccount surplus. B.save enough to funits investment spenng. C.buy assets from foreigners to funthe imbalance. is correct.A tra ficit must exactly matcheoffsetting capitaccount surplus to funthe ficit. A capitaccount surplus reflects borrowing from foreigners (increase in mestic liabilities) anor selling assets to foreigners (a crease in mestic assets). A capitaccount surplus is often referreto a \"capitinflow\" because the net effeis foreign investment in the mestic economy.考点The Tra Balance解析当一个国家出现贸易逆差时，就表明该国进口了更多的商品，出口了较少的商品。资本账户和经常性账户具有此消彼长的关系。经常性账户出现赤字，那么资本账户就会出现盈余，所以A正确。X-M=S-I+(T-G)根据题意，X-M减少可以产生，S-I减少。这表明国内储蓄的钱不够，需要国外资金支援建设，所以B错误。C也说反了，应该是外国人买国内资产以维持平衡，而不是国人买外国资产维持平衡。 按照X-M=S-I+(T-G)这个公式，如果有tra ficit，那代表 X-M是 小于0 的。 要改善这个情况，增加S难道不是方法之一吗？（选A是正确的原因我知道，请一下我的上述想法错在哪里）

NO.PZ2016010802000217 问题如下 A country with a tra ficit will most likely: A.have offsetting capitaccount surplus. B.save enough to funits investment spenng. C.buy assets from foreigners to funthe imbalance. is correct.A tra ficit must exactly matcheoffsetting capitaccount surplus to funthe ficit. A capitaccount surplus reflects borrowing from foreigners (increase in mestic liabilities) anor selling assets to foreigners (a crease in mestic assets). A capitaccount surplus is often referreto a \"capitinflow\" because the net effeis foreign investment in the mestic economy.考点The Tra Balance解析当一个国家出现贸易逆差时，就表明该国进口了更多的商品，出口了较少的商品。资本账户和经常性账户具有此消彼长的关系。经常性账户出现赤字，那么资本账户就会出现盈余，所以A正确。X-M=S-I+(T-G)根据题意，X-M减少可以产生，S-I减少。这表明国内储蓄的钱不够，需要国外资金支援建设，所以B错误。C也说反了，应该是外国人买国内资产以维持平衡，而不是国人买外国资产维持平衡。 外国人买本国商品，本国revenue增加，本国居民saving也增加，所以减少了tra flicit？