Once the habit is established, then you can vary your wake-up times or occasionally go without the alarm if you want to sleep in, but until then it's best to keep the pattern very tight.

一旦你养成了这个习惯，你可以改变起床的时间或是在没有设定闹钟的情况下去睡觉，不过在那之前你要严格保持这种模式。

youdao

I am very surprised that my roommate is a night until about two o 'clock in the morning to sleep off hand, and wake up the table on the stolen mobile inexplicable.

我也觉得很惊讶，我的舍友当晚是在凌晨两点钟左右才关手提睡觉的，醒来桌上的手提莫名其妙的就被盗了。

youdao