You can not imagine the difficulty they had ____ the problem. It isn’t ____ easy.
―Thank you for your beautiful flowers. ― _____ Happy birthday to you!
Shirley stood in the empty room, ______ so lonely for the first time.
Cheer up! It won’t be ______ we can meet again.
They stood there and ______ each other as if they were going to fight.
The president did much for world peace. That was ______ he was awarded the Nobel Peace Prize.