Plural forms of Nouns - Practical Course of English

The vast majority of compound nouns form their plurals by adding -s to the principal word (shown in bold) in the compound. Mainly it is a Noun. Examples: He now has two mothers-in-law. (plural of . mother-in-law). Editor-in-chief – editors-in-chief, Brother-in-law – brothers-in-law, Looker-on – lookers-on ................
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