什么是热传导？
参考答案：
在同一物体内或直接接触的几个物体之际间如存在温度差，就有热量传递这种现象叫热传导。
听句子，缩写原文。（）
A．We decided to sell the car when the oil Prices rose.
B．We should not delay solving the problem of oil prices.
C．We were at a loss as to whether to buy that expensive car or not.
D．We didn’t buy a car because of the floating oil prices.
当过道中存在高度低于（）的物件时，必须设置明显的警告标志。
A.3.5m
B.2.5m
C.2.0m
D.3.0m
