wear thin   (TTS發音)

1. become thin from use變薄；磨薄

    His old pair of pants has worn thin at the knees. 他舊褲子的膝蓋處已經磨薄了。

2. decrease；grow less or less interesting減少；漸漸變得無趣味

    The joke began to wear thin when you heard it too many times. 這個笑話聽過好幾遍以後就沒有什麼趣味了。