李敬之《汴河直进船》诗： “汴水通淮利最多，生人为害亦相和。东南四十三州地，取尽膏脂是此河。”该诗描述的是( )。

A．春秋后期，吴开凿大运河

B．元代开通大运河

C．北宋汴京的繁华

D．隋炀帝开凿大运河

The building around the corner caught fire last night. The police are now _____ the matter. [ ]

A. seeing through

B. working out

C. looking into

D. watching over