“未被理睬”常见的英文表达有 “be ignored”、“be left unnoticed” 或 “be overlooked”。以下为具体解释和例句：
1、 be ignored
含义：最直接、常用的表达，意为“被忽视”“被不理睬”。
例句：
His suggestions were completely ignored during the meeting.（他的建议在会议上完全被忽视了。）
She felt ignored when no one responded to her email.（当没人回复她的邮件时，她感到被忽视了。）
2、 be left unnoticed
含义：强调“未被注意到”，有一种“被晾在一边”的感觉。
例句：
His contribution to the project was left unnoticed by the team.（他对这个项目的贡献被团队忽略了。）
Her efforts were left unnoticed, which made her feel frustrated.（她的努力未被注意到，这让她感到沮丧。）
3、 be overlooked
含义：意为“被忽略”“被忽视”，常指因疏忽或未被充分重视而未被理睬。
例句：
His talents were often overlooked by his teachers.（他的才能经常被老师忽视。）
The problem was overlooked at first, but later it caused serious trouble.（这个问题起初被忽视了，但后来造成了严重的麻烦。）