介质的毒性程度为极度、（）或设计上不允许有微量泄漏的压力容器，必须进行气密性试验。
参考答案：高度危害
_______his knowledge of the mountainous country, John Smith was appointed as our guide.
A．In spite of
B．On account of
C．Regardless of
D．Instead of
一台机械的功率是300W，表示______．
