Tenses
Present Am/is/are+Iing 1. actions happening now, at the moment of speaking Now, at the moment, these I am writing a lettesat
Continuous 2.actions happening around the time of speaking days, at present, tonight etc. the moment.
3. fixed arrangements in the near future
Past Simple + II / -ed 1. actoins which happened or finished at a definite time in the past Yesterday, last I went to the gym
-?did+I 2. actions which happened repeatedly in the past but don't happen night/week/year/month, wtc, a yesterday.
anymore. In this case we can use adverbs of frequency month/two years/three years