心衰患者上一楼或步行50米时呼吸困难，其NYHA心功能分级为（）.
A.Ⅰ级
B.Ⅱ级
C.Ⅲ级
D.Ⅳ级
E.Ⅴ级
参考答案：C
Mary writes __________ than __________ boy in her class.
A．more careful; the other
B．more carefully; any other
C．more carefully; the other
D．more carefully; any
如何测量油挡的间隙？
