某种商品若按标价的八折出售,可获利20%,若按原标价出售,可获利[ ]
A.25%
B.40%
C.50%
D.66.7%
答案:C
Her brother ______ be at home now, because he was seen playing basketball in the stadium just now.
A.mustn’t
B.needn’t
C.can’t
D.shouldn’t
生产负荷一定,入尿素界区的CO2气压力升高时,CO2压缩机耗功()。
A.增大
B.减少
C.不变
D.无法确定