They were the tip of an iceberg.

这还只是冰山的一角。

youdao

Only the tip of an iceberg pokes up above water.

只有冰山的尖端突出于水面。

youdao

The airliner crash is seen as merely the tip of an iceberg.

这次飞机坠落被看作仅仅是冰山一角（只是其中的一个例子）。

youdao

Those who want reform say the magistrates touch only the tip of an iceberg.

ECONOMIST: French justice

It seems at least as likely that they merely reveal the tip of an iceberg.

ECONOMIST: Does the end justify the means?

Many suspect that the opportunities currently being exploited by the clean-up industry in Japan are merely the tip of an iceberg.

ECONOMIST: Toxic waste in Japan