Jack enjoys casual wears . you find him wearing a tie once in a blue moon 杰克喜欢休?的服装，千载难逢才见到他结领带。
Our boss is a miser . he gives us a treat only once in a blue moon 我们的老板是个铁公鸡。他招待我们一顿可真是千载难逢。
You will be able to see a dinosaur once in a blue moon . why don ' t you go to the exhibition 很难有机会看到恐龙的。为什么不去看看那个展览？
Coin collecting is interesting , but you find a real valuable coin only once in a blue moon 硬币收藏很有趣，不过得到一个真正有价值的货币几乎是不可能的。
If the river overflows its banks , the garden gets flooded ; but that only happens once in a blue moon 河水一旦泛滥，这片园子就会淹没，但这种情况极为罕见。
I shall always remember the time ( when ) i shook hands with the general . such things happen only once in a blue moon 我永远不会忘记与将军扬的那一刻.这真是千载难逢
If your bankroll has taken a huge , once in a blue moon hit , then it ' s probably best to take a break 如果你已经输了很多，那么一旦有人中出一手匪夷所思的好牌，你最好休息一下。
Of course , i grant you , to concede a point , you do knock across a simple soul once in a blue moon 我不认为这是个恰当的字眼。当然喽，我勉强承认，人们极偶然地会遇上一个单纯的灵魂。
My girlfriend helped me wash dishes this evening ； it ' s once in a blue moon . usually , he doesn ' t do any housework at all 译文：今晚我的女友帮我洗了碗，真是千载难逢啊。通常，她根本不做家务活的。
