She was still there two hours later when his breathing grew more shallow.
After four days of traveling, the river grew too shallow for the boats.
Over the past few hours his breathing had grown more shallow and rapid.
I could hear his breathing grow shallow, more ragged as he got closer.
The woman's breathing had grown shallower, her entire body in shock.
After about an hour the angle of the snowfield grew more shallow.
At last the water grew too shallow for swimming.
But now already she was entering yet another stretch of the stream where the water grew too shallow for swimming.
Sean followed and when the water grew too shallow, the fish turned back, but he was in another dry grotto.
And before long, especially with the Rat, the water grows so shallow that you can no longer sail or pole.