下颌骨体部的骨化中心位于（）

A.下颌神经出颅处

B.下牙槽神经与舌神经所形成的夹角下方

C.切牙神经和颏神经所形成的夹角下方

D.切牙神经的末端附近

E.颏神经的末端附近

As one of the tools and techniques of activity sequencing, a lead （）.

A．directs a delay in the successor activity

B．could be accomplished by a finish to-start relationship with a delay time

C．means the successor activity cannot start until after the predecessor is completed

D．allows an acceleration of the successor activity