Dwarves, although JRR Tolkien who helped edit the Oxford English Dictionary, maintained that Dwarfs is also correct.
Buffalos
Shelves
Mitochondria
cargoes or cargos
sheep, it doesn't change.
The plural of activity of activities.
Children or kids
Crises -- pronounced krahy- - seez
oxen - eg. a team of oxen pulled the plough
Successes is the plural form of the noun success.
phenomenons; for example, they were hit with many phenomenons. :) hope this helpss :D
The plural of calculus is generally "calculi." The word "calculuses" is also a plural, but very rare.