be fast asleep

基本解释

You can't think, see, and seize it, as if your body were vacated, nothing in it. All is so tranquil seems to be fast asleep.
想不能想，看不能见，捉不及物，身体好像不再有感觉，形同虚设，一切都是那么平静，似乎要睡着了。
blog.sina.com.cn
When the first streak of sunlight reaches the depth of several grottoes, the others may continue to be fast asleep and even remain in dark all day long.
每天清晨第一缕阳光照进几座洞窟深处时，另外的洞窟却可能继续沉睡不醒，甚至终日处于黑暗之中。
http://dj.iciba.com
Quite true, they are always trying to destroy us. I fully admit the soundness of this appraisal, and indeed one would have to be fast asleep to overlook the point.
对的，他们总是在企图破坏我们，我完全承认这种估计的正确，不估计这一点就等于睡觉。

MRS. OBAMA: Before Santa comes to your house you have to be fast asleep, okay?
WHITEHOUSE: The White House