【单选题】Last year, Joan bought 50 pounds of hamburger when her household ’s income was $40,000. This year, her household income was only $30,000 and Joan bought 60 pounds of hamburger. All else constant, Joan...
A.
negative, so Joan considers hamburger to be an inferior good
B.
positive, so Joan considers hamburger to be a normal good and a necessity
C.
positive, so Joan considers hamburger to be an inferior good
D.
negative, so Joan considers hamburger to be a normal good but not a necessity
【简答题】Competition considered as the main thing in life is too grim, too tenacious, too much a matter of taut muscles and intent will, to make a possible basis of life for more than one or two generations at...