"these" vs "this"

This and these are demonstratives, which means they indicate a specific noun in a sentence. The two words are similar because they refer to nouns that are near in space and time. This is used with singular or uncountable nouns (i.e. this egg or this music). These refers to plural nouns (i.e. these cookies). When the noun is omitted after this and these, they become pronouns (i.e. turn this off when you leave).

Demonstratives are words we use to indicate nouns in a sentence. They point out specific nouns that are near or far in time and space. Demonstratives clarify the difference between an apple and this apple. The four most common demonstratives are this, that, these, and those.

This

This refers to a singular noun that is near in time or space. We also use this for uncountable nouns that we treat as singular. The noun that follows must be written as a singular noun.

• This cupcake is delicious. (singular noun)
  
• I want this necklace for Christmas. (singular noun)
  
• What is this music you’re listening to? (singular uncountable noun)
  
• Get a grip on all this anger. (singular uncountable noun)
  

This is often used to talk about time. It can be used to talk about time in the present or in the near past or near present.

• My mom called me this morning. (near past)
  
• What’s for dinner this evening? (near future)
  
• I had three cancellations this week. (present)
  
• This year has been difficult for my family. (present)

These

These also refers to nouns that are near in time or space, but it is used for plural nouns. The noun that follows these must be plural.

• Where did these papers come from?
  
• Let me hand you these boxes.
  
• These musicians are talented.

That and Those

Similar to this and these, that and those are also demonstratives. They refer to nouns that are far in time or space. That is used for singular or uncountable nouns. Those is used before plural nouns.

• Hand me that apple over there. (singular noun, far away)
  
• What is all that noise outside? (singular uncountable noun, far away)
  
• Those meetings are tomorrow. (plural noun, far away in time)
  
• Let’s buy those toys. (plural noun, far away in distance)

Using Demonstratives As Pronouns

We can also use demonstratives as pronouns. If the subject or object is clear, we can omit the noun following the word.

• Mix sugar and milk. Heat this on the stove. (This refers to the sugar and milk.)
  
• Let me give you these. (It’s clear that these refers to whatever someone is giving.)
  
• These are the times that try men’s souls. (The noun comes later in the sentence. These times are the times would be redundant.)
  
• That is delicious! (That refers to whatever you just ate.)