kind
You use kind to talk about a class of people or things. Kind is a countable noun. After words like all and many, you use kinds, not ‘kind’.
It will give you an opportunity to meet all kinds of people.
The trees were filled with many kinds of birds.
After kinds of you can use either the plural or singular form of a noun. For example, you can say ‘I like most kinds of cars’ or ‘I like most kinds of car’. The singular form is more formal.
People have been working hard to produce the kinds of courses that we need.
There will be two kinds of certificate.
After kind of you use the singular form of a noun.
I'm not the kind of person to get married.
She makes the same kind of point in another essay.
In conversation, these and those are often used with kind. For example, people say ‘I don’t like these kind of films' or ‘I don’t like those kind of films'. This use is generally thought to be incorrect, and it is best to avoid it. Instead you should say ‘I don’t like this kind of film' or ‘I don’t like that kind of film'.
There are problems with this kind of explanation.
How will we answer that kind of question?
In more formal English, you can also say ‘I don’t like films of this kind'.
This is the best way of interpreting data of this kind.
You can also use like this, like that, or like these after a noun. For example, instead of saying ‘this kind of film’, you can say ‘films like this’.
I hope we see many more enterprises like this.
I'd read a few books like that.
Companies like these represent an important part of our economy.
Sort is used in a similar way to kind.
➜ See sort
You can also use kind of to describe something in a vague or uncertain way.
➜ See sort of - kind of