A:buy
B:to buy
C:buying
D:to have bought
小明买了一台电脑,原价5600元,现在“百脑汇”对这种电脑打八五折出售,那么现在买一台这种电脑需要多少元钱?
用8分米长的铁丝围成的正方形,边长是多少分米?