铜绿假单胞菌（绿脓杆菌）感染表现为（）。
A.黄色脓性痰
B.黄绿色或翠绿色痰
C.微黄奶酪样痰
D.痰黏稠抽拉成丝
E.水样痰，内含粉皮样物
参考答案：B
-I regret having said those words to my daughter.
-If I you, I would apologize to her and have a heart-to-heart talk with her.
A．am
B．were
C．should be
D．had been
关系数据模型的三大要素为：关系数据结构、关系操作集合和关系______。
