为什么“鸟会飞”译作birds fly,而不是the bird can fly?

The birds can ( )(fly). (Birds) can fly but (fish) can't A the birds,fish B the bird The bird can fly in the The bird can fly in the sky. The birds can't fly without w_____ __ birds can fly in the sky. Bird can fly Can birds fly?----- Yes,() can All birds can't fly. which bird can't fly? birds can fly,birds fly两者的区别. Can you see the birds _______(fly) above the trees?