绝缘油除具有绝缘作用外,还兼有()和()作用。
参考答案:冷却;熄弧
蕨类植物只能生活在阴湿环境中的主要原因是[ ]
A.没有真正的根
B.没有输导组织
C.受精作用离不开水
D.只有根状茎
We regret that we were unable to effect shipment within the time limit.because you failed to establish the relevant L/C in time.