慢性充血性心衰的心功能可分为()级。
A.Ⅰ
B.Ⅱ
C.Ⅲ
D.Ⅳ
E.Ⅴ
参考答案:D
You ________ cross the road when the traffic lights are red. [ ]
A. mustn't
B. can't
C. may not
D. don't
账户余额查询程序中记录的状态灯为黄灯时,则表明该余额为上次查询出的历史余额。