试描述在下列情况下，吸收和总需求会发生什么变化： a．外国人购买本国产品增加； b．国内

居民购买进口产品增加，但他们的总消费保持不变； c．私人投资者购买国内产品增加，但他们的总进口保持不变； d．政府提高税收。 Describe what happens to absorption and aggregate demand under the following circumstances： a．Foreigners buy more domestic goods． b．Domestic residents buy more imported goods，but their total consumption is unchanged． C．Private investors buy more domestic goods and leave their total imports unchanged． d．The government raises taxes．