在进入封闭空间之前，要测量（）和可能存在的有毒蒸汽和毒气。
A、测量氧气的浓度
B、测量氮气的浓度
C、测量气压
D、测量水蒸汽压
参考答案：A
Guess what! I came across my primary school science teacher this morning, ______ I have lost touch for almost 20 years.
A．of which
B．when
C．with whom
D．who
属于液化性坏死的是
A．肾梗死
B．脑梗死
C．肠梗死
D．心肌梗死
E．脾梗死
