单项选择题

One day while a girl was walking in the woods she found two starving songbirds. She took them home and put them in a small 11 . She cared for them and felt great love for them.
Once the 12 and stronger of the two birds flew from the cage. Therefore, 13 he flew close, she grasped him 14 . She felt glad, but suddenly she felt the bird go limp. She opened her hand and 15 in horror at the dead bird.
She noticed the other bird moving back and forth on the edge of the cage. She could feel his great need for 16 . She lifted him from the cage and 17 him softly into the air. The bird circled once, twice, three times.
The girl watched delightedly at the bird"s enjoyment. Her heart was no longer 18 with her loss. Suddenly the bird flew closer and 19 softly on her shoulder. It sang the sweetest melody that she had ever heard.
The fastest way to 20 love is to hold on it too tightly, while the best way to keep love is to give it WINGS!