Reported speech
When we are saying what other person say, think or believe. When we tell people what someone has said in the past, we generally make the tense "more in the past".

Example:
You look very nice.
I told him he looked very nice.

Direct                                 Reported
Today -----------------------  That day
Tonight ---------------------  That night
Last week ------------------  The previous week
Next week -----------------   The  following week
Yesterday ------------------   The day before
Tomorrow -----------------    The following day
This -------------------------   That
These -----------------------    These

Reported questions

The question change to a present tense.

Example:
 How much do you weight?
He asked me how much I weigh.