1.   Did the ancestors of birds first fly by gliding from the treetops, or did they run fast along the ground and jump into the air?

2.   Different birds fly over, different words when you cuss.

3.   The shag carpet was replaced with neutral-colored tiles, which are easy to clean after the birds fly free through the house.

4.   Only when he finished playing the flute did the birds fly out and went away.