It is used sometimes in the singular and sometimes as a plural.
Commonly sphinxes, sometimes sphinges.
The plural form of the word "curriculum" is "curricula" or sometimes "curriculums."
The Latin plural, sometimes used for verse or for the medical term, is cola.The English plural is colons, which is always used for the punctuation marks.
Libretto is the singular. Libretti is the plural. Sometimes librettos is also commonly used as the plural.
Sometimes they are pluralized by adding 's.
The plural of bento is bento. The Japanese obtain the pluralization through context and not by adding something to the word. It can be challenging sometimes!
The plural of phenomenon is phenomena.Phenomena is the usual plural of phenomenon. Phenomenons can sometimes be used as well in nonscientific writing when the meaning is "extraordinary things, occurrences, or persons".
No. *** Sometimes. 'Needs' as a verb (a child needs shoes) is not a plural. But 'needs' as a noun is indeed a plural ( A person's basic needs are food shelter water and clothing.)
The plural would be a normal S plural, twos. As a numeral, 2s is recommended, but the generally frowned-upon apostrophe version (2's) is sometimes clearer.
"Sisters" is appropriate anyway, but the alternate "sistren" is sometimes used.
Feu d'artifice or ( sometimes plural) feux d'artifice.