危险化学品从业人员必须接受培训，考核合格，持证上岗。
参考答案：对
Curling’s溃疡的出血和穿孔多发生在烧伤后________周。
This school is different ________ others. It has many out-of-class activities.
A．Off
B．from
C．of
D．for
