Сделать посивный залог из предложения "we (to have) clean air if we (to protect) the nature on our fragile planet" можете сразу написать ответ а не правило. нужно ! зарание .

We will have clean air if we protect the nature on our fragile planet.
Our family will have a picnic if it isn't foggy and rainy weather the day after tomorrow.
My friends will give the bread to the pigeons when they visit the Trafalgar Square.
If I have a lot of money, I shall give it to the ill children