sleep的词性可以是动词和名词,动词可以做谓语、动词不定式和动名词 现在分词短语,
sleeping的词性可以是动名词,现在分词,可以做主语、宾语、定语和伴随状态的状语.
sleepy,asleep 的词性都是形容词,
sleepy是表示性质的形容词,可以形容人感到昏昏欲睡,比较疲乏,例如He is very sleepy.The boy is a sleepy man.
asleep是表示状态的形容词,如He falls asleep.他躺倒就睡.I found him asleep in the classroom.