陶瓷与金属的扩散焊，既可在真空，又可在氢气气氛中，进行。
参考答案：对
In the traffic accident, an girl was badly hurt this morning. [ ]
A. eight-years-old
B. eight year old
C. eight-year-old
D eight-years old
社会主义民主政治的本质是：
A．人民当家作主B．人民民主专政C．人民代表大会制度D．人民参与国家管理
