There was a downfall.
It was King Peter's downfall.
The downfall of the city.
The market experienced a downfall.
Yes you can, but I think you would usually use this word in a past sentence or maybe a future sentence: past - Alcohol led to his downfall present - Alcohol will be his downfall
He went downfall as he fell of the cliff.
The demise of his father brought a downfall on their livelihood.
The actions of the people during the downfall of Communism was iconoclastic.
Greed is the downfall of many corrupt politicians.
The internecine conflict within the family business ultimately led to its downfall.
Can you use the word concluding in a sentence? Done.
You can use the word Truss in a sentence like this.
I can't believe you would have the audacity to ask me anything.I am appalled at your audacity.Your audacity will be your downfall.
To this day, historians argue over what caused the Roman empire's downfall.
Just use it! Or do you mean, can you use the word beheld in a sentence.
How do you use the word decibel in a sentence?What is decibel used for?