废热锅炉的液面计为什么要定期检查?
参考答案:
为了了解锅炉内液面的高低,保持液面在操作参数内,确保现场与操作室DCS指示相同,防止烧干锅炉发生事故。
Jack wasn't saying anything but the teacher smiled at him ____ he had done something very clever.
A as if B in case C while D though
下列哪项不属于体液免疫的效应
A.ADCC效应B.中和作用C.补体介导的调理作用D.抗体介导的调理作用E.DTH反应