单项选择题
A.6 B.7 C.8 D.9
A.N B.N+E C.E D.N-E
A.t->prior->next=t->next;t->next->prior=t->prior; B.t->prior->prior=t->prior;t->next->next=t->next; C.t->prior->next=t->prior;t->next->prior=t->next; D.t->prior->prior=t->next;t->next->prior=t->prior;