Besides, if you say you do something on Sunday (s), Monday (s), etc. , it also conveys the sense that you do it on every Sunday, Monday, etc. So you can also say: It's something I do on Sunday or Sundays instead of It's something I do every Sunday that is more clear and emphatic.
For instance, Easter is always on (a) Sunday, and Thanksgiving Day is always on the fourth Thursday in November. We don't say Thanksgiving Day is on Thursdays because that would imply it is celebrated every Thursday of the year.
A native speaker would most likely say: I met him last Sunday morning. or I met him last Sunday, in the morning. This: On last Sunday morning is grammatically correct, but wouldn't be used that often. Although you could say it, it would sound a bit strange and a native speaker mostly wouldn't use it. You would just say 'last Sunday morning', without the preposition. On the morning on last ...
time - Can I say "in the Morning, last Sunday" - English Language ...
1 If today is Sunday (or any day) and you say, "This Sunday" it means "this coming sunday." That is what "this Sunday" is short for. If you say, "next Sunday" it is referring to the following after a previously stated Sunday, or the following Sunday after "this Sunday" with the understanding that person you are talking to knows what this Sunday ...
Sunday’s general election has been cast as a high-stakes contest between democracy and military rule, but critics say a new army-backed constitution gives junta-appointed officials a large say in the next government.