That battle is of great significance when viewed in the perceptive of the progress of the war

That battle is of great significance when viewed in the perceptive of the progress of the war
意思：这场战斗非常重要,当这场战役的细密的进程被看穿的时候.
1.be of great significance
be of 加名词,表示形容词意思.相当于,be significant(adj)
2.when 引导的是时间装语从句.viewed是非谓语动词,因为和主句的主语battle是被动的动宾关系（战役被人看穿,而不是战役看穿）,所以不用主动的viewing,而用viewed.
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