瓦斯灾害仍是制约煤矿安全、威胁矿工生命的“第一杀手”。
参考答案：对
By hiking, people can ______ nature and experience a kind of life.
A．close to
B．close the
C．get close to
D．get close to the
简述用户选择电极功率的原则？
