A听不到B在说什么(hear),所以根本无法专心地听(listen)。这两个字不能在同个场景。
举个例子:(online class)
A: Teacher, are you talking? I can't hear you.
B: Yes, I am. (types in chat: If you still can't hear me, please check your mic or reenter the meeting. )
B: Why do conifer leaves have thick waxy layers? Can C answer my question?
C: Huh?
B: C, are you listening? Please pay attention in class.