The singular form of these is this. They are an English word, mainly used as determiners, pronouns and adjectives. When used as a determiner, it means these, and when used as a pronoun, it means these. Let me take you to see articles about these singular forms.

When used as an adjective, the singular form 1 means these. It means: (referring to close people or things) this, this; (of people or things already mentioned) this; (used when introducing people or showing things) Here, here. This is my book. This is (that is) my book. These books are mine. These (those) books are mine.

1. demonstrative pronouns this and that are the two most basic and commonly used words in English, and their basic usage is as follows: (1) this is generally used to refer to people or things close in time or space, and its plural form is these. This is a pen and these are pencils. This is my friend, Mary. This is my friend, Mary. This is a book. This is a book. (of nearby objects)

(2) that refers to people or things that are far away in time or space, and its plural form is "that". This is my bedroom. That's your bedroom. This is my bedroom and that is your bedroom. These are American stamps and these are China stamps. These are American stamps and those are China stamps. (3) When two things are introduced together, use this first and then use that. This is a pen. That's a pencil. This is a pen and that is a pencil. When using different demonstrative pronouns, we should pay attention to the consistency of the singular and plural predicates.

The singular form 2 has no singular form.

These are Britain [i:z] and America [iz]

Among them;

Pronouns these;

[Example] Go to an interest-bearing current account and keep credit. Most banks and large building societies now offer these accounts.

Turn it into an interest-bearing current deposit account and leave the balance in the account. Most banks and large building societies can now open such accounts.

In there be sentences, the verb be is plural and singular;

1. There is only one subject: if the subject is a singular countable noun or an uncountable noun, the verb be is singular; If the subject is plural, the verb be is also plural.

2. There are two or more parallel subjects: if the first subject is a countable noun singular or an uncountable noun, the verb be is singular; If the first subject is plural, the verb be is plural.

Note (1) In the American TOEFL test, if there are two or more parallel subjects, the verb be can only be plural. (2) In informal English and spoken English, is can also be used with plural subjects. But it is best not to use it in the exam, otherwise it may be judged as an error and deducted points.