Mum was so tired that she fell________as soon as she went to bed．
A.asleep
B.sleepy
C.sleeping
D.sleep
网友回答
A解析分析：fall asleep(“入睡”)，fall原来的意思是“落下”“跌倒”，用作不及物动词。此处fall意为“进入某种状态”，用作连系动词，后接形容词作表语。sleepy是形容词，“想睡的”，不符句意。sleeping也可以用作形容词，“在睡觉的”，如：a sleeping child．