the tip of the iceberg

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