loss是名词:损失, 遗失, 失败, 输, 浪费, 错过
His death is a loss for us.他的死对我们来说是个损失
lose是动词;遗失, 浪费, 错过, 输去, 使失去, 使迷路, 使沉溺于
They lose many books just now.他们刚刚丢失了很多书。
lost是形容词:失去的, 丧失的, 错过的, 迷惑的, 不为人知的;
She was lost in the forest last night. 她昨晚在森林里迷路了
同时也是lose的过去式。
词性不同,用法也就不同,跟汉语一样。
参考资料:http://zhidao.baidu.com/question/34888086.html?si=2