bottom: 1.the lowest part of sth 底部,最下部
2.the lowest surface on the insude of a container（容器內(nèi)的）底
3.the ground below the water in a lake, river, swimming...（湖,河,游泳池等的）底,水底
4.the part of sth that is furthest from you, you house......的盡頭
eg. there is a stream at the bottom of the garden花園的盡頭有一條小溪

ground: 1. the soild surface of the earth地面；地通常用作the ground
2.soil on the surface of the earth 土；土地；土壤
3.an area of land that is used for a particular purpose, activity or sport（特定用途的）場地
4.an area of interest, knowledge or ideas（興趣,知識,思想的）范圍,領(lǐng)域
ground常指室外, 地面

land: 1.the surface of the earth that is not sea陸地
2.(涉及感情或想象）國家,地區(qū) motherland祖國
land 強調(diào)海陸的對比

floor: 1.the surface of a room that you walk on室內(nèi)的地板,地面
2. the bottom surface of a vehicle（車廂內(nèi)的）底板

仔細觀察你會發(fā)現(xiàn)這些詞的側(cè)重點死不一樣的,查字典時一定要看英文解釋和例句,因為有些時候中文是比較不出來的