If you see about half of your arch, you have the most common foot type and are considered a normal pronator.
如果你能看到约半个足弓，那么你是最普遍的足型，旋前肌也正常。
2
Large-span arch truss steel bridge is a common superstructure of trestle bridge on open sea.
大跨度拱桁式钢引桥是外海开敞式深水码头栈桥常用的上部结构型式之一。
3
Bridge turning construction is a common kind of bridge construction technique. But the open thin-walled boxes technology is a new kind of arch bridge construction technology recently.