— I went to Tom's birthday party last night. A lot of my good friends were there too.  

— It ________ fun.   [      ]

A. must be      

B. can be    

C. must have been      

D. can have been

确诊早期听神经瘤的理想方法是（）。

A.X线平片

B.桥小脑池空气造影

C.脑池造影CT检查

D.超声检查

E.MRI检查