I think that the world will be an easy place to live in. We1have machines and robots and they will2us do all the3jobs, and we don't have to do things4washing dishes and5the beds, though we won't have any dishes at all. Maybe we will just throw the dishes away after each meal. I6that doctors will be able to7us alive8a long time. I hope that when I am 80 years old, there9something that can keep me alive for1080 years, so I will live to be 160 years old.

历史总是有着惊人的相似，这一规律在元、明、清三个朝代中的主要表现有（    ）

①都实行中央集权的政治制度    ②都加强各民族之间的联系

③都结束分裂局面实现大一统    ④都由少数民族建立的政权

____从宇宙空间拍摄的地球照片，更改证明地球是球体了。