“have one too many”的意思是（非正式）多喝了一杯（酒），微醉，喝多了，贪杯了。

【例句】
He must seem to have had one too many. You'd better walk him home.
看他那个样子肯定是喝多了。你最好把他送回家。

You must have had one too many last night.
你昨天晚上肯定喝了很多。