帮忙翻译三个句子，翻译好的，追加50分~谢！

1. Americans who would be patriots must try to learn what it is that they have in common, what it is in the republic that is worth cherishing and preserving; until they know that, their patriotism will have no more content than a bright, loud afternoon parade.
欲成为爱国人士的美国人必须竭力明白他们有什么共同点，共和体里有什么值得珍惜和保留的。等到他们明白了，他们的爱国主义将不再有什么内涵而只是一场光天化日、大吵大闹的午后游行。

2. Computer language may range from detailed low level close to that immediately understood by the particular computer, to the sophisticated high level which can be rendered automatically acceptable to a wide range of computers.
计算机语言层次不同，可从接近于被特种计算机立即理解的详尽低层次语言到被大量计算机接受的可自动识别的尖端高层次语言。

3. From the time when our caveman ancestors gnawed their wild-pig bones in front of their smoking fire to our own days when we sit around a table spread with snowy linen and shining silver, we have the history of the change in eating habits from the simple satisfaction of hunger to the meal as a delightful, if rather complex,