Teenagers and young adults should aim for nine hours or more.

VOA: special.2010.06.09

so for about six, oh, no, it was nine hours a day, it's a long time ago.

每天要上六个，噢，不是，是九个小时的课，这都是很久以前的事情了。

纽约的人们 - SpeakingMax英语口语达人

For about nine hours a day, I would be in these acting classes,

每天我都要上差不多九个小时的表演课，

纽约的人们 - SpeakingMax英语口语达人