A、In a building. B、In a tree hole: C、in a cave. D、All of the above. D

Owl is the general name for over 130 types of birds from three families, and most of them are active at night. When the owl flies, its wings are noiseless just like those of a butterfly because the wing’s surface is similar to velvet. The owl’s feathers are light and dark brown in color. The size of the female owl is larger than the male. An owl usually builds a nest in a building, a tree hole of an abandoned nest of other birds, and some even make their nests on the ground or in a cave. Owls mainly eat insects, birds, small mammals or fish and most of them live on mice. An owl has sharp ears and eyes, and its face can help reflect the sound to its ears during night travel so as to determine the direction of a hunting target. China has 26 out of the world’s 132 owls. About 120 of them are typical owls with large prominent eyes and round tails. Owls’ size varies from 13 to 15 centimeters to up to 70 centimeters or even larger. They live across the world except the South Pole, and most of them like to live in forest areas. Ancient Chinese literary works recorded the descriptions of owls. Owl’s folk names as "night cat" and "cat’s head eagle" derive from its habits and appearance. The Chinese government has listed the bird and one of the wildlife for the state second class protection.