非谓语:现在分词tired of sleeping on the floor

非谓语:现在分词tired of sleeping on the floor新概念49课有一句子1)Tired of sleeping on the floor, a young man in teheran saved up for years to buy a real bed.这句句子可以还原成:A young man in teheran saved up for years to buy a real bed because he is tired of sleeping on the floor.我想问一下,这句从句能否改成以下分词结构? 如果可以,又与第一句分词结构句子有什么区别? 如果不能改,原因又是什么?2)Being tired of sleeping on the floor, a young man in teheran saved up for years to buy a real bed.希望能说的详细些,是不是说在语法结构上都是可以的,强调的时间不同?