Present Continious
if something is right happing right now e.g It is cumming.
Present Perfect
if somehting started at an unknows Point in the past and its still going on e.g It has returned
Present Simple
used for Routines/Habbits e.g These numbers fluctuate
Past Tense
if something started in the past at a exact time and is over e.g In 2019 it increased