_________the difficult problem,the professor continued to do his experiment.     [ ]

A. Having solved                              

B. Solved    

C. Solving                                   

D. Having been sloved

下列关于梅毒性心脏病的描述，错误的是()

A．主动脉起始部瘤样扩张

B．主动脉根部搏动增强

C．左心室增大

D．心尖闻及舒张期杂音

E．胸主动脉迂曲、延长