____, I have never seen anyone who’s as capable as John.

A．As much as I have traveled

B．Now that I have traveled so much

C．Much as I have traveled

D．As I have traveled so much

畸胎瘤的特征性X线征象是（）

A.肿瘤位于前纵隔

B.肿瘤呈圆形，卵圆形成分叶状

C.肿瘤内有密度减低区

D.肿瘤内有气影或牙齿影

E.肿瘤壁呈弧形钙化