For plans, arrangements and intentions in the future
SHOULD/SHOULDN'T
For abilities in the present and in the past
CONDITIONAL 1
For important finished short actions that interrupt other. Also, for consecutive actions
MUSTN'T
For predictions in the future, decisions at the moment and promises
To talk about something probable or possible in the future. There must be IF and a consequence or result
To give advice, to say something is or isn't a good idea
MUST/ HAVE TO/HAS TO/ HAD TO
PAST CONTINUOUS
BE GOING TO
CAN/CAN'T/COULD/COULDN'T
For secondary long actions that are interrupted. Also, for two actions happening at the same time in the past
For things that are prohibited
To talk about obligation in the past and in the present
PAST SIMPLE
WILL
