第一类永动机。
参考答案：
不消耗任何能量而能连续不断作功的循环发动机，称为第一类永动机。
Secondary and higher education _____ available to all high school graduates in this country so far.
A．have made
B．were made themselves
C．have been made
D．were made it
头针的针刺深度应该是针尖达到
A．呈60°夹角B．呈30°夹角C．帽状腱膜上层D．帽状腱膜下层E．头皮下层
