headquarters
The plural of headquarters remains headquarters.
Headquarters is a plural noun. It has no singular form
Headquarters is both singular and plural.
The possessive form of the plural uncountable noun headquarters is headquarters'.example: The headquarters' staff will be here for training on Monday.
Headquarters is a compound word.
The word crises is a plural word; it is the plural form of the word crisis.
It would be incorrect to say "this headquarters"... it would have to be "those headquarters." I've never heard it used in any singular form. You would have to say "this headquarter" which is never used.
The plural is offices.
There is no plural word for if.
The plural word for delay is delays.
The plural form for the demonstrative pronoun this is these.
A non-plural word, a word (noun or pronoun) that is not plural is singular, a word for just one.