Though trying really hard, they acknowledged ____ at last.

________ the right decisions ________ the future is probably the most important things we'll ever do in our lives.

On the wall of his office _________the paintings of early French artists.

Rare species in the world, ______ by hundreds every year, must be jointly preserved by all countries, or humans will encounter ecological disaster in the near future.

Peter sat on the train seat, with his eyes ____ on the fields outside the window.