fall asleep ,fall 不是动词吗,asleep 是形容词,能用来修饰动词?还是因为是一个固定词组?

fall asleep是不是形容词修饰动词 fall asleep是短暂动词吗? fall asleep是延续性动词词组还是非延续性动词词组? fall加什么词fall asleepasleep是形容词 但fall不是系动词 怎么能用形容词修饰呢? fall asleep 是动词短语吗 那请问 l have a hard time falling asleep eve asleep是动词吗 还是sleep是动词 fall asleep join begin fall asleep borrow的延续性动词怎么变 fall是动词还是系动词 fall asleep 与drop asleep asleep sleepy fall asleep feel asleep 区别 fall down是动词吗?