--- There is ________dark stain(污渍) on my coat. Who left it?---- It’s me, Dad. I did it just for ______ fun.
Standing inside ____ lots of strange creatures with white skin and large black eyes.
—I have been waiting for you so long. —Sorry, I have been in the library, _______ my friend look for some books.
I think humour is a vital form of entertainment, ____ it makes us laugh and laughing keeps us healthy.
The UN is an important international organization _____helps many people around the world.
When you get on stage for the first time, you may be surprised by ______bright the lights are.