18. ----- Has Mary finished writing her article ?

----- No, and it _____ before class was over.

A．should be finished

B．should finish

C．should have finished

D．ought to have been finished

密斯·凡·得·罗一生对建筑的贡献是( )。

A．创建了有机建筑论
B．善于运用钢筋混凝土等新材料
C．运用钢框架结构和玻璃为现代建筑手段
D．提倡走工业化道路