In English, we have the word "the" which can be either singular or plural. For example, we can say: "the shop" and "the shops" and the word "the" doesn't change.

We know that this is not the case in Māori, where the singular word for "the" is "te" and the plural word for "the" is "ngā" - te toa (the shop) and ngā toa (the shops).

However, in English we have the words "a" and "some" which do change in the singular and plural. We say: "a dog" and "some dogs". We don't say: "a dogs" or "some dog".

Strangely, the word for "a" and "some" don't change in Māori. The word is he which can either mean "a" or "some".

He kurī can either mean "a dogs" or "some dogs". How are you supposed to know which one it is? Well, you don't, unless there is some context that tells you. But its the same problem we might have in English if someone says: "the farmer boight the sheep". Did he one sheep or several sheep? You don't know. Or: "the boy caught the fish". Did he catch one fish or lots of fish? You don't know, and it probably doesn't matter.

In the same way he ika could mean "a fish" or "several fish". 

For example:

Kei te oma he kurī.
A dog is running.
or:
Some dogs are running.

Kei te hīkoi he pirihimana.
A police officer is walking.
or:
Some police officers are walking.

There are some words that change in the plural, and so we can know if we are talking about one person or more than one person by whether or not the vowel is lengethened.

For example:

Kei te waiata te wahine.
A woman is sining.

But:

Kei te waiata he wāhine.
Some women are singing.

And:

Kei te noho he tangata.
A person is sitting.

But:

Kei te noho he tāngata.
Some people are sitting.