give oneself away   (TTS發音)

show guilt；show one has done wrong 洩露罪行；露馬腳；現原形

    The thief gave himself away by spending a lot of money. 小偷大量揮霍鈔票而露了馬腳。

    His accent gave himself away. 他的口音暴露了他是哪兒人。