----- Nội dung dịch tự động từ ảnh ----- Score: 0 happy express 19:43 singing looking for home beautiful SUBMIT People usually sing because they like music or because they feel happy. They (1)__ their happiness by singing. When a bird sing, however, its song usually means much more than that the bird is happy. Birds have many reasons for (2)_-- . They sing to give information. Their songs are their language. The most (3)_-- songs are sung by male (cock) birds. They sing when they want to attract a female (hen) bird. It is their way of saying that they are (4)_-- a wife. Birds also sing to tell other birds to keep away. To a bird, his tree or even a branch of tree, is his (5)--- · He does not want strangers to come near him, so he sings to warn them.