—He spoke ______ fast _______ I didn't follow him.
A:so; that
B:too; to
C:very; that
设异面直线l1,l2的方向向量分别为a→=(﹣1,1,0),b→=(1,0,﹣1),则异面直线l1,l2所成角的大小为____
唐朝在世界上享有很高声誉,各国称中国人为____。