main supports的用法和樣例：
例句
- The cables, which will be the bridge's main support, are strung from tower to tower. They are made up of wire that's high tensile steel.
作為大橋的主要支撐，繩索被繃在塔之間。它們是由高抗拉強度的鋼絲組成的。 - A horizontal beam, as of steel or wood, used as a main support for a building or bridge.
大梁一水平的鐵制或木制的桁條，用來(lái)作為建筑物或橋梁的主要支撐物
