如图,把△ABC沿AB边平移到△DEF的位置,它们重叠部分的面积是△ABC面积的一半,若AB=,则此三角形移动的距离是
A.
B.
C.1
D.
答案:A
After a long walk, they______ pass over the mountain.
A. could be able to
B.can
C.would
D.were able to
影响耐火极限的因素有哪些?