影响加热炉热效率的主要因素有（）等。
A、排烟温度
B、炉墙散热损失
C、过剩空气系数
D、仪表指示
参考答案：A, B, C
.I think _________ of the materials I listened to at the beginning of the exam ____ easy.
A．three fourths; is
B．third four; are
C．three fourths; are
D．third fourth; are
为防止“小装量效应”，脉动真空压力蒸气灭菌器的装载量不得小于（）
A.5%
B.10%
C.15%
D.20%
E.25%
