Present tenses
describing habits and routines
present simple
a past action with specific time
past simple
events which may or may not happen in the future
future simple
for advice
should
present perfect changes to ...
past perfect
timetables and schedules
present simple
when two actions happened simultaneously
past continuous
an action will be still in progress at a specific time in the future
future continious
obligation because you want to do that
must
past continuous changes to
past continuous
how long an action happened
present perfect
when the action happened at UNspecified time in the past but the Subject is dead
past simple
predictions based on evidence
to be going to
obligation out of your will
have to
the previous year
arrangements (when date and location are usually planned)
present continuous
when an action happened in the past, at UNspecified time in the past and the result was in the past
past perfect
an action will be finished before a specific time in the future
future perfect
guesses about past events
may/might/ could have V3
in wh... questions ... is used instead of that
wh... itself
annoying behaviour (with always)
present continuous
when action continued for some time and finished in the past, with a past result
past perfect continuous
making promises/ threats/ warnings
future simple
criticising past actions
should have V3
in yes/ no questions ... is used instead of that
if/ whether