腰椎间盘突出症与椎管内肿瘤最有鉴别意义的辅助检查是（）。

A.X线检查

B.CT

C.MRI

D.肌电图

E.超声波

34. I can’t thank you ______ much because without your help I ______ have won the first prize.

A．too; wouldn’t

B．very; shouldn’t

C．that; might not

D．so; couldn’t