"Mail" is a mass noun, so it adopts the grammar of a singular noun ("The mail is here." "Has the mail arrived yet?"), although it cannot be pluralised (1 mail, 2 mails) or combined with an indefinite article (a mail).
Other examples of mass nouns are "luggage" and "advice".
Mail is both singular and plural. You could receive one piece of mail or you could receive lots of mail.
Are is plural. "Is" is singular. For example, "There is a glove on the chair". That is singular. "There are gloves on the chair". That is plural.
Who may be singular or plural.
diagnosis is singular diagnoses is plural sis = singular ses = plural
Atrium is singular - the plural is atria.
Mail is both singular and plural. You could receive one piece of mail or you could receive lots of mail.
Yes, "mail" can refer to both singular and plural forms. It is used in a singular form when talking about a single piece of mail, such as "I received a piece of mail." It is used in a plural form when talking about multiple pieces of mail, such as "I need to check my mails."
practitioner is singular (plural practitioners)sofa is singular (plural sofas)satellite is singular (plural satellites)clips is plural (singular clip)dentist is singular (plural dentists)dollars is plural (singular dollar)article is singular (plural articles)magazines is plural (singular magazine)laminator is singular (laminators is plural)radios is plural (singular radio)
singular and plural
Singular: book / Plural: books Singular: cat / Plural: cats Singular: child / Plural: children Singular: foot / Plural: feet
Are is plural. "Is" is singular. For example, "There is a glove on the chair". That is singular. "There are gloves on the chair". That is plural.
"Has" is singular, e.g. He has, she has. "Have" is plural, e.g. They have, we have. The exception is "I" - e.g. I have.
The word team is singular; the plural form is teams.
This is singular. These is the plural form.
These is plural, this is singular
'These' is the plural form of 'this'.
Who may be singular or plural.