Theory:

Look at the following two sentences:

John said, 'I am unwell now.' - Sentence 1.

John said that he was unwell at that time. - Sentence 2.

Sentence 1 is called Direct speech, because it uses the actual words spoken, and sentence 2 is called reported speech speech, where the words used by the speaker are reported, just as a journalist would do.

Because Reported speech happens after Direct speech, by definition, there are some changes which take place:

The verb goes one step into the past:

play becomes played

played becomes had played

a full list of these verb changes will be given here.

The pronoun also changes from I to He.

Any time element would also change, and in the case of questions, the position of the auxilliaries also changes.

Let's look at some examples:

'I played tennis yesterday,' said David  Direct speech

David said that he had played tennis the day before.  reported speech.

Notice:

I becomes He

Played becoes had played

yesterday becomes The day before

In the case of a question, there are 2 possibilities:

A question which accepts a yes or no answer

Do you like chocolate?

and one that only accepts one answer.

Where is my hat?

Let's look at both cases:

Do you like chocolate?' asked Maria  direct speech

Maria asked me IF I liked chocolate.  reported speech

Notice the presence of IF, which is not used with questions with only one answer, and like changes to liked.

Where is my hat?' asked Maria  direct speech

Maria aske me where her hat was.  reported speech

Notice MY changes to HER, there is no IF, is changes to was, and the position of the auxilliary is changes.

We often use the word SAID in reported speech, but there are many other possibilities for this word, and these are commonly tested in the FCE

In reported speech WILL goes to WOULD and CAN goes to COULD.