请告诉我为什么选这个选项及为什么其它的选项是不对的呢？
He is so talkative a person that he will __________ whenever he gets an opportunity.
A talk his head off
B talk the head off
C speak his head off
D say his head off
答案为A

下面的是在词典上找到的例句。所以应该选A talk his head off/说个没完没了的意思。这个talk one's head off是固定搭配。其它的都没有那种形式。


He'll talk your head off if you give him a chance.
他一有机会就会对你说个没完。
No,they think she is obnoxious.She loves to talk her head off.
不，他们认为她讨厌；她喜欢讲话讲个不停。