We must create a safe and ______ international environment of lasting peace.
The next thing he saw was smoke ______ from behind the house.
They began to think about what use could be ______ such materials.
Tom ______ close the window when his attention was caught by a bird.
He has made some spelling mistakes in the paper; ______, they are not serious.
I ______ say he ______ speak to her in public at that time, for he was such a shy boy.