5．A ______(私人) car gives a much greater degree of comfort and mobility.

4．The old man entered the room ______(搀扶) by his grandson.

3．The government ______(宣布) that they would build a new highway to the mountain.

2．No one is born ______(完美的). You just need to be practical and self－confident.

1．Man is fighting a ______(战斗) against pollution.

15．D

14．B。根据句意可知他和外界“隔绝”了，故用cut off。

13．A。本题考查独立主格结构的用法。句意：考虑了所有的因素之后，原来计划好的旅行不得不取消了。本句中的consider与all the factors之间为逻辑上的动宾关系，在句子中要用被动形式，因此排除C、D两项，前后两部分不是并列的分句，要采用“名词+过去分词”形式的独立主格结构作时间状语，相当于after all the factors are considered，此处的独立主格结构也可改写成with all the factors considered。