If something is telling, it shows the true nature of a person or situation.
显露真相的How a man shaves may be a telling clue to his age. 一个男人如何刮脸也许会暴露他的实际年龄。
Juan sat quietly through the telling of this saga.
胡安安静地坐着听完了这个长篇故事。
She wasn't telling the whole truth.
她没有把实情都讲出来。