Reported speech (Indirect speech), или косвенная речь — это речь, передаваемая не слово в слово, а только по содержанию, в виде дополнительных придаточных предложений, без сохранения стилистики автора.

• present simple

I like ice cream (прямая)
She said (that) she liked ice cream. (косвенная)

• present continuous

I am living in London
She said (that) she was living in London.

• past simple

I bought a car
She said (that) she had bought a car OR She said (that) she bought a car.

• past continuous

I was walking along the street
She said (that) she had been walking along the street.

• present perfect

I haven't seen Julie
She said (that) she hadn't seen Julie.

• past perfect*

I had taken English lessons before
She said (that) she had taken English lessons before.

• will

I'll see you later
She said (that) she would see me later.

• would*

I would help, but...
She said (that) she would help but...

• can

I can speak perfect English
She said (that) she could speak perfect English.

• could*

I could swim when I was four
She said (that) she could swim when she was four.

• shall

I shall come later
She said (that) she would come later.

• should*

I should call my mother
She said (that) she should call her mother

• might*

I might be late
She said (that) she might be late

• must

I must study at the weekend
She said (that) she must study at the weekend OR She said she had to study at the weekend

now- then / at that time
today-yesterday / that day / Tuesday / the 27th of June
yesterday- the day before yesterday / the day before / Wednesday / the 5th of December
last night- the night before, Thursday night
last week- the week before / the previous week
tomorrow- today / the next day / the following day / Friday
here-there