Question

怎么理解下面这句话中“as”的用法？

Researchers found that only people who were seated in the same row as a passenger with the flu, for example -- or one row in front of or behind that individual -- had a high risk of catching the illness.

这里的 as 是做介词吧（应该不是作连词，毕竟没有引导从句）？
但是它作介词的意思是“prep. 当作；以…的身份；如同”，其中也好像没有一种意思与句子吻合啊？
难道这里是 same ... as 的用法？

Answer 1

连词 相当于when 前后宾语一致省略when a passenger with the flu seated in the same row 。若从句的主语和主句的主语不一致，但和主句的宾语一致时，从句中的主语和be动词亦常可省略。例如：
Father advised me not to say anything until (I was) asked.Granny told the children not to talk while (they were) eating. You must attend the meeting unless (it is) inconvenient to you.除非情况对你来说不方便,否则你必须出席这次会议。

Answer 2

四年时间里，他去过无数次顾惜的学校找她，可始终没有见过顾惜。毕业之后，余大城留在了这个城市，惜家也留在那里了。兔斯基很老了。只能靠注射营养液维持生命，余大城很怕它的生命就这样走向尽头。那个周末顾惜去小动物保护基地做义工，被派到宠物医院取注射液。

Answer 3

是主语补足语。