The plural for for the compound noun sister-in-law is sisters-in-law.
The rule is that the 'sisters' become multiple, but the relationship 'in-law' does not become multiple, it is still the same relationship to a siblings spouse.
Note that you will hear people say, 'my in-laws'. This term is used when the 'in-laws' are relationships of varying combinations of sister, brother, father, mother-in-law and the abbreviated form is easier to say.
The plural form of sister-in-law is sisters-in-law. The rule for forming the plural of compound nouns like this is to pluralize the main noun (sister) rather than the modifier (in-law).
To form the plural of a compound noun, you generally add -s to the main noun in the compound if it's a regular plural form. For example, "book" in "bookstore" becomes "bookstores" in the plural. If the compound noun doesn't have a main noun, you can add -s to the end of the entire compound (e.g., "brother-in-law" becomes "brothers-in-law").
To form the plural of a word, typically add "s" or "es" to the end of the word. However, there are irregular plural forms where the word changes entirely (e.g. child to children). Use a dictionary or grammar guide for exceptions.
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)
You seem to have the singular and the plural lumped into one word. The singular is diagnosis; the plural is diagnoses. They are the singular and plural forms of a common, abstract noun.
The rules for making proper nouns plural are the same as for making common nouns plural. The plural form is the DaVincis.
Rules of thumb
To form the plural of a word, typically add "s" or "es" to the end of the word. However, there are irregular plural forms where the word changes entirely (e.g. child to children). Use a dictionary or grammar guide for exceptions.
the word "rules" (in the plural form) cannot take any prefixes.
The correct phrasing would be "Don't forget those libraries' rules." The apostrophe is placed after the s to indicate possession by multiple libraries.
To form the plural of a compound noun, you generally add -s to the main noun in the compound if it's a regular plural form. For example, "book" in "bookstore" becomes "bookstores" in the plural. If the compound noun doesn't have a main noun, you can add -s to the end of the entire compound (e.g., "brother-in-law" becomes "brothers-in-law").
Possess is a verb. Its plural form (the one used with plural subjects) is possess, while the form used with singular subjects is possesses.Examples:We possess, they possess.He, she or it possesses.The noun form of possess is possession, plural possessions.
a cow
Fungi is the standard plural of fungus, because the word is Latin in origin it follows the Latin rules for plurals, however funguses following the English rules for plurals is also now an approved plural of fungus due to its frequency in common usage.
In English, the most common way to form the plural of a noun is by adding "-s" or "-es" to the end of the word. However, there are many irregular plural forms that do not follow this rule, such as "child" becoming "children" or "man" becoming "men." It's important to learn the specific plural forms of irregular nouns.
The possessive form of the plural noun charters is charters'.Example: All of the previous charters' rules will be reviewed for relevance.
Eros is a proper noun; proper noun use the same rules for plural as common noun. Words ending in ch, sh, z, x, and s add -es to the end of the word to form the plural. The plural form is Eroses.