Heard losts of times,the song doesn't sound as nice as hefore 为什么用heard 而不能用having heard?
问题描述：
Heard losts of times,the song doesn't sound as nice as hefore 为什么用heard 而不能用having heard?
讲明区别和为什么
答
having done强调原因,一般做原因状语
heard 只是表示听过之后,强调先后