低厂变的铭牌上为什么有两个额定容量？
参考答案：低者是自然风冷的容量，高者是强迫风冷的容量。
Tina _____ have known the truth, or she would have told us.
A．mustn't
B．shouldn't
C．can't
D．needn't
燃烧的类型有()。
A．自燃
B．着火
C．闪燃
D．阴燃
E．爆燃
