New digital mobile phones definitely produce less radiation, but that doesn’t mean that they should be used without caution.
A. generally
B. ultimately
C. relatively
D. necessarily
网友回答
A. generally
B. ultimately
C. relatively
(答案→)D. necessarily
解析：考查固定词组。固定词组Not necessarily未必，不一定就…；句意：先的手机的辐射一定会小一点，但是未必就意味着他们可以没有顾忌地被使用。故D正确。