FrancophonIA/Vikidia-EnFr huggingface dataset:
A sentence is a group of words that are put together to mean something. A sentence is the basic unit of language which expresses a complete thought. It does this by following the grammatical basic rules of syntax. For example: 'Angela is the cutest girl in the class'.

A complete sentence has at least a subject and a main verb to state (declare) a complete thought. Short example: Walker walks. A subject is the noun that is doing the main verb. The main verb is the verb that the subject is doing. In English and many other languages, the first word of a written sentence has a capital letter. At the end of the sentence there is a full stop or full point (American: 'period').

A phrase or clause is part of a sentence.[1]p773–777

This is an example of a sentence:

In this sentence, 'The dog' is the subject, and 'is' is the verb.

This is an example of a phrase:

There is no verb, so we do not know anything about what the happy dog is doing. Therefore, it is not a sentence.

A clause is a sentence within a sentence. Example:

Sentences have different purposes:

Here are some sentences written in Basic English:

The sky is blue.

Today is Monday.

Tomorrow is Tuesday.

The baby is smiling.

Sheila is reading a book.

This is the road to take.

Read a book about the history of America.

There are beautiful flowers growing in the garden.

The cushions are new and I feel the comfort they give me.

They are playing in the grounds.