Can many be followed with singular noun?

No, "many" is a plural quantifier, meaning it refers to more than one of something. It cannot be directly followed by a singular noun.

Examples:

* Correct: Many people were at the party.

* Incorrect: Many person was at the party.

If you want to express a large number of a singular item, you can use a phrase like "a lot of" or "a great deal of" instead of "many."

* Correct: A lot of water was spilled.

* Correct: A great deal of money was spent.