As it grew darker, I drifted in and out of sleep.

For the next few days, he drifted in and out of sleep, mostly.

He seemed to be drifting in and out of sleep, gasping for strength to form words.

Then, once you've found a seat, you start reading the paper and soon you're drifting in and out of sleep.

For many tendays after that, he drifted in and out of sleep.

Alertness came slowly as he drifted in and out of uneasy sleep.

Maggie Rose kept drifting in and out of sleep.

For a long time Luke drifted in and out of sleep.

She didn't know how long they stayed like that; she drifted in and out of sleep.

The young man drifted in and out of sleep for a while, until he heard voices.