用千克表示
____
水结成冰后,体积增加了 111 ,冰融化成水后,体积减少了____.
After working all day,he was so tired that he was in no______to go to the party with us.
如图所示,AB=CD,BC=DA,E,F是AC上的两点,且AE=CF,求证:BF=DE.
用灯光作为太阳光,演示地球的自转和公转,读图回答问题.