肺癌放疗布野时需要注意（）

A、尽量保护正常的肺组织

B、不必保护正常肺组织

C、治疗过程中不考虑脊髓受量

D、不必挡铅

E、不考虑病灶位置

I am very thankful to my English teacher,           I have made great progress.      [ ]

A. by whose help              

B. with whose help      

C. with his help              

D. by his help