In general, a plain carpet makes a room look bigger...
He placed the paper in a plain envelope...
He wore a plain blue shirt, open at the collar.
Bronwen's dress was plain but it hung well on her...
It was a plain, grey stone house, distinguished mainly by its largely unspoilt simplicity.
It was plain to him that I was having a nervous breakdown...
He's made it plain that he loves the game and wants to be involved still.
...a shy, rather plain girl with a pale complexion.
Once there were 70 million buffalo on the plains.
The food was just plain terrible.
Why couldn't they call you plain Ann or Alice like the rest?
Three officers in plain clothes told me to get out of the car.