The plural of spectrum is "spectra."
Spectra is the plural of spectrum. You could discuss the spectrum generated by an element in a star, and comparing more than one element, you would be comparing spectra. (Latin -um words form plurals like this, so you cannot refer to them as spectrums. Another example is datum, singular, and data, plural.)
The plural form of the noun 'spaceship' is spaceships.
The plural form of the noun sky is skies.The plural possessive form is skies'.
Orbits is the plural form for the noun orbit; the plural possessive form is orbits'.
The possessive form of the plural noun orbits is orbits'.
Spectra is the plural of spectrum. You could discuss the spectrum generated by an element in a star, and comparing more than one element, you would be comparing spectra. (Latin -um words form plurals like this, so you cannot refer to them as spectrums. Another example is datum, singular, and data, plural.)
The noun spectacles is a shortened form for the term 'pair of spectacles'. The plural form is two pairs of spectacles.The nouns spectacles belongs to a group of nouns that are a shortened form for 'a pair of', for example:binocularsglassespantsscissorsshearsshortsspectaclestongstrouserstweezersAll of these nouns are made plural by changing 'a pair of...' to 'pairs of...'.
The plural form of "do" is "do" and the plural form of "don't" is "don't." These words do not change in the plural form when used in a sentence.
The plural form of him, her, or it is them. (objective pronouns)
Bridges is the plural form of bridge.
The plural form of "was" is "were."
"Groceries" is the plural form of "grocery."
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.
The plural form of "meter" is "meters."
The plural form of the demonstrative pronoun 'that' is those.
The plural form of "trench" is "trenches."
The plural form for the noun sergeant is sergeants; the plural possessive form is sergeants'.