Every day you point at things and talk about whose things they are. In a shop you say, How much is this jacket? At home you say, Those shoes are dirty. At the office you ask, Is this your phone? The words this, that, these, and those let you point with your voice. The words my, your, his, her, its, our, and their say who owns something. Without them, simple moments become confusing.

These small words also carry number and distance. If you say, These bag is my, your listener hears three problems at once: these does not match one bag, and my cannot stand at the end alone. Getting this pattern right makes you sound careful and clear, and it costs you only a few minutes of practice.

There are two small families here. The first family points: this, that, these, those. We call them demonstratives, which just means pointing words. The second family shows the owner: my, your, his, her, its, our, their. We call them possessive determiners, which just means owner words that come before a noun.

The pointing words follow two rules: distance and number. This is for one thing near you: this cup in my hand. That is for one thing far from you: that car across the street. These is for two or more things near you: these keys here. Those is for two or more things far away: those birds in the sky. So near or far chooses this/these versus that/those, and one or many chooses this/that versus these/those. These bag is wrong because these is plural and bag is singular. Say this bag or these bags.

The owner words always come before a noun: my phone, your idea, his desk, her car, its door, our house, their children. They never change for number: my book, my books. English has a second set that stands alone, without a noun: mine, yours, his, hers, ours, theirs. Compare: This is my bag (owner word plus noun) and This bag is mine (standing alone at the end). Wrong: This bag is my. Right: This bag is mine, or This is my bag.

One more important rule: the space before a noun has room for only one determiner. You cannot stack them. Wrong: the my keys, this my phone. Right: my keys, this phone, or my phone. If you want to point and show the owner together, use this pattern: this phone of mine, or simply say, This is my phone.

Pronunciation helps too. This has a short sound, like miss. These has a long sound, like cheese. Many mistakes with these words come from hearing them wrongly, so practice the pair out loud: this dish, these dishes.

1. 1. This coffee is too hot, so I will wait.

   This points to one thing near the speaker, right in their hand.

2. 2. That building across the road is our bank.

   That points to one thing far away; our shows the owner before the noun.

3. 3. These tomatoes look fresh, but those onions look old.

   These is near and plural; those is far and plural, in one sentence.

4. 4. Is this your umbrella, or is it hers?

   Your comes before a noun; hers stands alone without a noun.

5. 5. My sister lost her keys at the gym yesterday.

   My and her each sit directly before their nouns.

6. 6. Whose jacket is this? It is not mine.

   Mine stands alone; you cannot say it is not my.

7. 7. Their apartment is small, but its balcony is lovely.

   Its shows that the balcony belongs to the apartment, a thing.

8. 8. Can you pass me that plate on the top shelf?

   That fits one far thing; use those for two or more far things.

9. 9. These shoes hurt my feet after a long walk.

   These matches the plural noun shoes; this shoes would be wrong.

10. 10. Our flight leaves at noon, and their flight leaves at three.

    Our and their compare two owners of similar things.

11. 11. I do not like this song. Can we play that one?

    This works in a negative too; that one points to a different song.

12. 12. His doctor said that these pills work quickly.

    His marks the owner; these matches the plural noun pills.

13. 13. Are those your children playing in the park?

    Those and your can sit in a question about far, plural things.

14. 14. This is our stop, so grab your bag now.

    This stands alone as a pointer; your still needs its noun, bag.

The most common mistake is a number mismatch. Learners say, These bag is my, mixing a plural pointer with a singular noun. Wrong: These bag is heavy. Right: This bag is heavy, or These bags are heavy. The pointing word and the noun must agree: this and that go with one thing, these and those go with two or more. Check the noun first, then pick the pointer.

The second mistake is confusing the two owner sets. My, your, and her need a noun after them; mine, yours, and hers stand alone. Wrong: This phone is my. Right: This phone is mine. Wrong: That is mine car. Right: That is my car. A simple test: if a noun comes next, use the short form (my); if the sentence ends or the noun is gone, use the long form (mine).

The third mistake is stacking determiners. Learners translate word by word and say, the my friend or this my house. English allows only one determiner before the noun. Wrong: the my friend. Right: my friend. If you really need both ideas, change the shape of the sentence: This is my house, or a friend of mine.

• Near: this and these. Far: that and those.
• One thing: this or that. Many things: these or those.
• Noun coming next? Use my, your, her. No noun after? Use mine, yours, hers.
• Never stack determiners: say my friend, never the my friend.
• Match the pointer to the noun: this bag, these bags.
• Practice the sound pair out loud: this (short) versus these (long, like cheese).