rain
The plural form of 'rain', is 'rains'.
The plural form for nimbus (grey rain cloud) is nimbi.
The plural noun is 'rains', an uncountable noun as a word specifically for seasons or periods of rain.The noun 'rain' is a singular, uncountable (mass) noun as a word for water drops falling from clouds.The word 'rain' is also a verb: rain, rains, raining, rained.
It is singular. "The rain is falling." To be plural, the usage would be something like "the rain drops are." (rain would be an adjective)
There is no plural form. Do and Do not are verbs
The plural form of him, her, or it is them. (objective pronouns)
Bridges is the plural form of bridge.
Thunder as a noun is a sound produced by lightning, so it normally has no plural form. Occurrences at two separate times or places would remain "thunder."
The plural form of "was" is "were."
The plural form of "I" is "we."
The plural form of "is" is "are."
No, "rain" is not a plural noun. It is a singular noun that refers to water falling from the sky in drops.