The best way to deal with an impolite person is to _____ him. [ ]

Li Ping, was there a traffic accident on Western Street last night–Yes. Twenty-five people died. It’s _____one that I have ever heard of

Do you ever practice English with your friends–Yes, I do that

It is definite that new digital mobile phones have less radiation, but that does not ______ mean that they should be used without caution[ ]

Within the last year, scientists have come closer than ever .