Tammy: I don"t know what to do about my father. Mattle:What"s wrong with him?
Tammy: It"s his health. He doesn"t take care of himself.
Mattle:Have you tried talking to him?
Tammy: I could talk to him till I"m blue in the face, and it wouldn"t work.
Mattie: What about his doctor?
Talk till someone is blue in the face费尽唇舌
字面的意思为“讲到某人的脸色发青为止”，形容苦口婆心劝解或“费尽唇舌”说服。例如： You can talk till you"re blue in face about it.but it is not going to changeanything.(就算你讲到口水干了，也不会有任何改变。)
Once in a blue moon难得一见地
blue moon(蓝月亮)是指“一个月中的第二次满月”。约每32个月才出现一次“一个月有两次满月”的天文现象。例如：You only clean your room once in a blue moon.(你会打扫房间还真是难得一见的事)。
