Fred and Jim did not like each other at first,but ______ they became friends.   [ ]

A. in time      

B. on time    

C. in turn      

D. by turns

逆行肾盂造影的禁忌证是（）

A.静脉肾盂造影显影不良

B.肾盂积水严重

C.先天性多囊肾

D. * * 狭窄

E.肾功能差