阑尾动脉是下列哪条动脉的直接分支（）
A.空、回肠动脉
B.右结肠动脉
C.肠系膜上动脉
D.回结肠动脉
E.肠系膜下动脉
参考答案：D
—Shall I inform him of the change of the schedule right now?
—I am afraid you _______, in case he comes late for the meeting.
A．will
B．must
C．may
D．Can
论述模锻时分模面的选择原则。
