病情危重，需随时观察者应采取
A．特级护理
B．一级护理
C．二级护理
D．三级护理
E．常规护理
参考答案：A
She won't let her daughter _____ by the river.[ ]
A. play
B. plays
C. to play
D. playing
某监测站测得空气中浓度为5.71mg/m试换算为ppm。
