下列芳烃中最难发生加氢反应的是（）。
A、单环芳烃
B、双环芳烃
C、三环芳烃
D、多环芳烃
参考答案：A
- Have you seen the New Year's film Personal TaiTor _______ by Feng Xiaogang?
- Yes. It was pictured in Suzhou, and it is well worth _______.
A．directing; seeing
B．directed; to be seen
C．directed; seeing
D．directed; being seen
精原细胞瘤，除发生在睾丸外尚可发生在：（）
A.肺内
B.前、中纵隔
C.颈部
D.后纵隔
E.膈肌附近
