蒸馏系统馏分质量差的处理方法有（）。
A、离交树脂切换
B、提高蒸馏负荷
C、控制较高的残液流量
D、据成品质量决定成品去向
参考答案：A, C, D
冷凝集试验可协助诊断的疾病是()
A．斑疹伤寒
B．非典型性肺炎
C．肠热症
D．梅毒
E．猩红热
I called Hannah many times yesterday evening，but I couldn't get through. Her brother_____ on the phone all the time!
A．was talking
B．has been talking
C．has talked
D．talked
