how often的音标？

I don't know how often I heard the same awful jokes.这种千篇一律的烂笑话我不知道听过多少回了。No matter how often they turn up, their welcome never wears out.不管他们多久露面一次，都永远那么受欢迎。How often do you give your phone number out?你经常把自己的电话告诉别人吗...

多久，多常...