To avoid the mistakes of our forefathers, the author suggests that______.

单项选择题According to the author, the greatest mistake of our forefathers was that______.

单项选择题The author's attitude towards tile current situation ill the exploitation of natural resources is______.

单项选择题It can be inferred from the third paragraph that earlier generations didn't realize

单项选择题According to the passage, it is the telephone that______.

单项选择题The author describes the telephone as impartial because______.