单词：bascules
(bascule 的第三人称 -s形式) n. 竖旋桥活动桁架
-s form of bascule
n. a structure or device in which one end is counterbalanced by the other (on the principle of the seesaw)
n. a structure or device in which one end is counterbalanced by the other (on the principle of the seesaw)