强调对某人/某物的主观认知或归类，等同于以下短语：
regard as
consider as
see as
think of as
结构：look upon + 宾语（sb/sth）+ as + 补语（n./pron./adj./doing等名词性成分）
（注：“as”后需接名词性成分，说明宾语的“属性/身份/类别”）
1、 主动句（常见）
They look upon him as a reliable friend.
（他们把他看作可靠的朋友。）
The team looks upon teamwork as the secret to their victory.
（团队将协作视为胜利的秘诀。）
I look upon learning a new language as a challenging but rewarding experience.
（我把学新语言看作既挑战又有收获的经历。）
2、 被动句（强调“被视为”）
She is looked upon as the best teacher in the school.
（她被视为学校里最好的老师。）
Environmental protection is increasingly looked upon as a global priority.
（环境保护越来越被视为全球首要任务。）
不可省略“as”：否则短语含义会改变（如“look upon sb”仅表示“看着某人”，无“视为”的意思）。
同义词替换：若需更正式的表达，可用“regard as”；若更口语化，可用“think of as”。