--Why are your group so happy?

--Our group _______ theirs in the oral English competition.

A．has won

B．have gained

C．has beaten

D．have defeated

主要用于中等跨度的桥梁的是下列的( )。

A．箱形筒支梁桥

B．肋梁式筒支梁桥

C．装配式筒支梁桥

D．整体式筒支梁桥