指出在下列情况下，价格水平有什么变化，指出是总需求还是总供给冲击引起了价格水平变化，变化是暂时的还是持久的。 a．由于恶劣的气候，今年庄稼的收成要大幅度降低。 b．国家卷入到战争中。 c．政府增加开支建造新的公共住房。 d．工会使工资增加了20％。 Describe whalt happens to the price level in the following cases．Identify whether it is an aggregate demand or an aggregate supply shock that caused the movement，and whether it is temporary or permanent． a．Due to bad weather．crops will be reduced significantly this year． b．The courttry goes to war． c．The government increases spending to build new public housing． d．Unions get a 20 percent wage increase．