Gettysburg address的一句话讲解谢谢!

gettysburg address详细解释（英语高手请进）
特别是 It is for us,the living,rather,to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced.It is rather for us to be here dedicated to the great task remaining before us---that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion;这几句,怎样翻译,为什么那么译,是什么句型,用了什么语法知识等等,

gettysburg address 语法分析
其实就是最后这个排比句,文章意思应该看懂,或者猜懂了吧 :)
it is rather for us to be here dedicated to the great task remaining before us---that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion; that we here highly resolve that these dead shall not have died in vain; that this nation, under god, shall have a new birth of ***; and that *** of the people, by the people, and for the people, shall not perish from the earth.
好多that啊.
(1)
that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion;
主要是这句,那位高人能理顺,谢谢了.
更主要是这里.we take increased.断句是在..take increased...中间吗,就是前面的东东都是要来increased的,可这里又是过去式啊,其实高清这句,后面的两个排比都清楚了.
还有,就是三个排比开头的that是指什么?