She tried to fall into sleep once more, but could not.

I spent the next half hour trying not to fall asleep.

That means you can try to fall asleep on your own.

He tried to fall back from it, but his hand was held firmly in the light.

"Get behind that tree, and try not to fall over anything."

All the matter tries to fall toward the center, and will if there's nothing in its way.

She lay down and tried to fall back to sleep.

But he was also trying not to fall clear out of his seat.

In this House too, we are all trying to fall into line and innovative ideas go by the board.

I sat listening to the music, trying not to fall asleep.