剪刀撑杆的接长采用搭接，搭接长度不得小于（），应采用不少于3个旋转扣件固定

（）forms over land，most frequently during autumn and winter over low-lying land，especially if it is damp and marshy and in valleys on quiet nights with clear skies.

A.FRONTAL FOG

B.MIXING FOG

C.ADVECTION FOG

D.RADIATION FOG