—Michael likes flying around the world.

—I think being a             is just right for him. [ ]

A. pilot

B. policeman

C. cook

D. doctor

皮肤科应用于放射治疗的是 ________ 线和 ________ 射线。此两种射线对增殖快、分裂迅速的细胞有明显抑制作用。