Question

sentence using the words plain and stain

Answer 1

The dark cloud was like a stain of darkness over the wide-open plain.
(Is that too advanced?)

There was a red stain on the boy's shirt as he stood in the grassy plain.
(That's a bit simpler.)

Answer 2

    These chips aren't good enough they are plain.                                                   Can you please get this stain off it making my clothes look dirty.