URGENT,PLEASE HELP!!QUESTION ABOUT MACRO ECON

首先, 睇下 GDP 既 components:
http://en.wikipedia.org/wiki/Gross_domestic_product#The_components_of_GDP
GDP = consumption + investment + (government spending) + (exports − imports)
GDP = C + I + G + NX
之後分析下 d events 會affect 邊個(幾個), 係正定負, 睇下個overall effect

Reduction in the standard workweek from 37 hours to 30 hours;
REDUCE GDP, since Investment is reduced (spending of labor), also C could decrease if as people earn less.

Hiring of all welfare recipients as government employees;
INCREASE GDP, since G is increased (之前welface payments 唔計落 G)

An increase in the amount of spending on devices that reduce pollution at a major hydroelectricity plant;
INCREASE GDP, since I (Investment) is increased

An increase in the amount of acid rain that falls;
INCREASE GDP, Investment may increase (repair items), NX may increase if the rain reduces food production(so have to import more or export less food)

Complete cessation of all imports from Europe;
INCREASE GDP, Import reduces, EX increases

Destruction of hundreds of businesses by an ice storm;
REDUCE GDP**, Investment probably increase (note: they have to repurchase the equipment, so increase Inv; on the other hand, some may stop running and so reduce the expenses on labor), but if it takes a long time to rebuild, the products they used to produce may have to be imported, so NX will decrease. The NET effect is hard to determine!

Destruction of thousands of homes by flood water;
INCREASE GDP, Investment increases, as people have to spend on household. (Spending by households on new houses is also included in Investment.)

最好睇埋 GPD 有咩 Limitations:
http://en.wikipedia.org/wiki/Gross_domestic_product#Criticisms_and_limitations
其實真係幾白癡....例如有SARS, gov spend 好多錢去醫人. 有地震, 要起過d樓...都會增加 GDP, 但個國家明顯唔係有咩好既增長....都幾有趣

希望有助你學習啦 ^^