the tip of the iceberg
US /ðə tɪp əv ði ˈaɪs.bɜːɡ/
UK /ðə tɪp əv ði ˈaɪs.bɜːɡ/

1.
冰山一角
only a small, visible part of a much larger, hidden problem or situation
:
•
The recent scandal is just the tip of the iceberg; there's much more corruption to uncover.
最近的丑闻只是冰山一角;还有更多的腐败有待揭露。
•
His current financial troubles are just the tip of the iceberg of his deeper debt problems.
他目前的财务困境只是他更深层债务问题的冰山一角。