后边并不是两个句子啊 ,第一个分句有while连接,是后面那个小句的状语从句.那后面小句的连词是什么? 还有"the old and that "中的"that"做什么讲?It is understood that the new bombs are more powerful than the old and it is understoodthat while one atomic bomb could obliterate Hiroshima, one hydrogen bomb could obliterate the largest cities such as London, New York, and Moscow.这样看结构可能会清楚点