单项选择题A.He went mountain climbing last year.B.He hasn’t traveled around the world yet.C.He’s always wanted to climb that mountain.D.He definitely does not want to go.
单项选择题A.The workers on the underground platforms were replaced by machines.B.It became the first completely automatic railway in the world.C.A completely automatic line was added to its network.D.Computers began controlling the trains on the line.