单项选择题
A.never happy B.never bored C.always tired D.always annoyed
A.To protect the boots from water. B.To protect the soles from heat. C.To protect the floors from soles. D.To protect the boots from rubber.
A.As its gases run out, it cools down. B.It collides with other stars. C.It can only live for about a million years. D.As it gets hotter and hotter, it explodes.