若3am+2b4与﹣a5bn﹣1的和仍是一个单项式,则m+n=____.
—No, it's not . It's .
—I usually go to school______the school bus.
如图,菱形ABCD的对角线AC与BD交于点O,AB=5,AC=6,点E,F分别在AD,CD上,AE=CF= 54 ,EF交BD于点H.将△DEF沿EF折到△ D′EF 的位置, OD′=10 .