had enjoyed 过去完成时
表示在过去完成的动作
They asked me to have a drink with them. I said that it was at least ten years since I had enjoyed a good drink.
他们邀请我与他们一起喝酒(have a drink 在国外通常指啤酒).
我告诉他们,已经有十年我没好好的和别人畅饮一番了.
(这里表示在十年前他才和别人好好的喝过一次酒,所以是过去完成时)
如：
They had planted six hundred trees before last Wednesday.
在上星期三前,他们就种好了六百颗树.（过去就完成了）
希望能帮到你!