MRI在横断位胰腺水平显示肠系膜上动、静脉常位于()
A.胰头、体交叉的前方
B.胰体的后下缘
C.钩突的右侧
D.钩突的前方
E.钩突的后方
参考答案:D
We're in class. You'd better not _______. [ ]
A. talk
B. talking
C. talked
D. to talk
简述童话的起源。