be heard to do be be heard to be doing be heard doing be heard to doing我知道前两个是对的,后两个存在吗?若存在四个进行比较,有何区别be heard to dobe heard to be doing be heard doing be heard to doing如果不存在，前两者请比较
问题描述：
be heard to do be be heard to be doing be heard doing be heard to doing
我知道前两个是对的,后两个存在吗?若存在
四个进行比较,有何区别
be heard to do
be heard to be doing
be heard doing
be heard to doing
如果不存在，前两者请比较
答