The old man enjoys collecting signatures of famous people _______ famous paintings. [ ]

A. with preference of

B. in preference to

C. in preference for

D. with preference to

产生下列问题的原因是：压力过大（）。

A．裂片 

B．粘冲 

C．片重差异超限 

D．小剂量片的均匀度不合格 

E．崩解超限