So all you need is a sentence with the word in it? You made one just by asking. But here are some others.
The number forty shows up in the Bible very often. The story of Noah's Ark says it rained for forty days and forty nights. The stories say that Jesus went into the wilderness for forty days and forty nights. That is why the season of Lent has forty days.
The number forty also appears in other stories. Ali Baba had forty thieves along with him.
The United States had forty presidents before George Bush senior was president.
Here are a few:
- Ten years ago, I was forty years old.
- The number forty comes after the number thirty-nine.
- The rains came for forty days and forty nights.
- Forty is a great age.
- Quarante is the French word for forty.
Now, why do you need a sentence for the word "forty"? How does your teacher want you to use the word in that sentence? As a noun, as in my sentences 2, 4 and 5? Or as an adjective, as in my sentences 1 and 3?
Try to give us more detailed questions.