肥胖病人术后易并发呼吸系统的并发症为（）。
A.哮喘
B.气胸
C.肺部感染和肺不张
D.限制性通气障碍
E.肺栓塞
参考答案：C
She is a quiet girl at school，but sometimes she _____ be very naughty.
A．should
B．would
C．will
D．can
