finishing touch
US /ˈfɪn.ɪʃ.ɪŋ tʌtʃ/
UK /ˈfɪn.ɪʃ.ɪŋ tʌtʃ/

1.
点睛之笔, 画龙点睛
a final detail or improvement that completes or perfects something
:
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Adding the small decorative vase was the perfect finishing touch to the room.
加上那个小装饰花瓶是房间完美的点睛之笔。
•
The artist added a few more brushstrokes as a finishing touch to the painting.
艺术家又添了几笔,作为画作的点睛之笔。