He has always had a chip on his shoulder because he didn't get the job.

had 是动词 have 的过去分词形式，表示"拥有、持有"的状态。 a 是不定冠词，表示"一个"。 chip 本义是"碎片、薄片"，在这里比喻为"不满的情绪"。 on 是介词，表示"在...上面"。 his 是形容词性物主代词，表示"他的"。 shoulder 意思是"肩膀"。 have a chip on one's shoulder 是固定短语，字面意思是"肩膀上有个碎片"，比喻"心怀不满、愤愤不平"的状态。