invariable

"My friend told me there was something in the box, but I didn't know what it was yet. "

"The words “big” and “heavy” are English adjectives."

"The constant noise from the construction site made it hard to concentrate on my homework. "

"The old factory showed a clear declension over the years, with peeling paint, broken windows, and overgrown weeds. "

"Your writing is not grammatical enough for publication."

"The conjugation of the different study groups led to a more productive learning environment. "

"an inflection for gender, number, or tense"

"Starting tomorrow, I will wake up an hour earlier to exercise. "

"My dad buys the local newspaper every morning to read about the school events and community news. "

"The library offered an extension on the due date for the overdue books. "

"The rules of the game are unalterable; we must follow them exactly as they are written. "

"He drank the water I gave him."