The ninteen fifities, or fifties.
potato - plural - potatoes
An apostrophe is used in situations when we refer to something being possessed. With the apostrophe is refers to plurals. For example: John's cars. Those are the cars owned by John. Mens clothes. This is wrong. Men is a plural itself. It should be: Men's clothes. 1950's best song. This is what was the best song in 1950, not in the years from 1950 to 1959. If you have a plural and possessive together, you can use the apostrophe after the s. Farmers' incomes. This refer to the incomes of many farmers.
Singular ' He/She is Plural 'They are NB Notice they change of verb. NNB 'They is' is NOT correct English.
The plural of 'this' is 'these' and the plural of 'that' is 'those'.
Isthmi is plural. There are actually two plural forms. I will list them from singular to plural. Isthmus - Singular Isthmi - Plural Isthmuses - Plural
The plural of rose is roses. The plural possessive is roses'.
A common mistake is to put an 's after a noun to make it plural this is incorrect (although some don't when used after non-words like "P's and Q's" or "in the 1950's")
The plural of 'bunch' is bunches.The plural of 'ant' is ants.The plural of 'batch' is batches.The plural of 'day' is days.The plural of 'chimney' is chimneys.The plural of 'tomato' is tomatoes.The plural of 'umbrella' is umbrellas.The plural of 'donkey' is donkeys.The plural of 'sky' is skies.The plural of 'foot' is feet.The plural of 'show' is shows.
applied is does not have a plural but is apply it does have a plural.
As you have given it. Singular ; Knight Plural ; Knights The word 'knight' comes from the Old English/Germainic word 'knabe' . In modern terms ' knave'.
The plural form of can is cans.
The plural is a regular plural, attics.