Tell me some riddles.

1, the two words are back to back, and the middle one is horizontally divided into north and south.

Sitting on a boat, you gain and you lose.

2. It rains above and the mountain falls below;

It is said that whether it rains or not, goose feathers fly all over the sky.

3. Say that the sky is not the sky, and that Yuan is not Yuan;

Say it isn't, but write it in front of you.