I got an e-mail this morning. It's _____ my best friend John. [ ]

A. in

B. on

C. at

D. from

绞窄性肠梗阻( )。

A．阵发性绞痛
B．持续性胀痛
C．持续性绞痛
D．阵发性钻顶样痛
E．刀割样腹痛