Identify the countable noun in the sentence.
The sheet of paper got wet in the rain making it difficult to identify its contents.
Paper
Contents
Rain
Sheet
In the context of the sentence, only ‘sheet’ is a countable noun. One can count sheets using numbers.
After the iron is out of the fire, bellows are used to blow air on it to cool it down.
Some people helped me find my luggage when I lost it in the crowd on my way back.
Skateboard manufacturers profit majorly from this fair.