下列哪种IgA肾病患者的预后最差()。
A.女性患者
B.以单纯性血尿为表现的患者
C.存在难以控制的高血压的患者
D.儿童患者
E.以上说法均不正确
参考答案:C
若幂函数f(x)的图象经过(4,2),则f(9)=______.
The boss has given everyone a special holiday, so we _____ go to work tomorrow. [ ]
A. can't
B. mustn't
C. needn't
D. shouldn't