Never go rafting unless you know how to swim.

除非你会游泳，否则的话就不要去漂流。

youdao

You should not go rafting unless you know how to swim.

你不应该去漂流，除非你懂得如何游泳。

youdao

You should not go rafting unless you know how to swim.

你不应该去漂流，除非你懂得如何游泳。

youdao