拉熔丝时，先拉负极，后拉正极，合熔丝时相反。
参考答案：错
The years between 1940 and 1970 is known as （）period.
A．the Reform Movement
B．odem Language Teaching and Research
C．Communicative Language Teaching
D．Structural Language Teaching
简单压力容器主要受压元件的最小壁厚是否有规定，如有，是如何规定的？
