语法语法问题 英语 语法 专家来看下

The journey out of Iraq could be the most dangerous one they make there.这句话中的they make there是定语从句 修饰 the most dangerous  one 省略了关系代词 that  因为 关系代词 作从句中的宾语 故可以省略 .
2.Once on the Iraq highways,the soldiers are the most vulneable they have been during their entire depolyment.they have been是省略 that 的定语从句 修饰 起名词作用的 the most vulneableduring their entire depolyment是介词短语作状语 修饰they have been the most vulneable
3.Even though officials say they`re below those levels, they admit it`s been challenging keeping up with what`s coming out of Iraq.keep加ing是现在分词 作状语 修饰 it`s been challenging 
4.The UAV may be a US aircraft that have been flying a mission over western Afghanistan late last week.
此句中的late和last week是 时间状语 修饰什么have been flyinglate不能换成laterlater前面是一段时间  用在一般过去时态中 如 two days later