YOU SAID:

You only know who's been swimming naked when the tide goes out

INTO JAPANESE

潮が引いたときに誰が裸で泳いでいたかしかわかりません

BACK INTO ENGLISH

I only know who was swimming naked when the tide was low

INTO JAPANESE

干潮時に誰が裸で泳いでいたのかしかわかりません

BACK INTO ENGLISH

I only know who was swimming naked at low tide

INTO JAPANESE

干潮時に誰が裸で泳いでいたのかしか知りません

BACK INTO ENGLISH

I only know who was swimming naked at low tide