关节内骨折最常见的并发症是

A．创伤性关节炎

B．缺血性骨坏死

C．骨化性肌炎

D．骨生成异常

E．骨折不愈合

—Some Chinese students find it hard to adapt to the life when in London.

—Exactly, ______ they've learnt a lot about the city before.[ ]

A. if only      

B. now that    

C. as though      

D. even though