sleepy与asleep这两个形容词均含有“欲睡的”之意。
sleepy : 最常用词，指人昏昏欲睡，或沉睡时的寂静状态。
- The heat and the wine made her sleepy.
周围暖洋洋的，又喝了酒，她感觉昏昏欲睡。
asleep : 作表语，多用于非正式的英语里，指处于睡着的状态，侧重动作的结果。
- He was so exhausted that he fell asleep at his desk.
他太累了，竟伏在书桌上睡着了。 - The police found him asleep in a garage.
警察发现他在一处车库里睡着了。
