Why we not use "on yesterday"?

[Kothow]

English Language Tests, Intermediate level

ESL/EFL Test #204 "Prepositions of Time and Date (2)", question 1

......... yesterday, I went shopping and found some great outfits for spring.

(a) On
(b) In
(c) (none)

English Language Tests, Intermediate level

ESL/EFL Test #204 "Prepositions of Time and Date (2)", answer 1

Yesterday, I went shopping and found some great outfits for spring.

Correct answer: (c) (none)

Your answer was: incorrect
On yesterday, I went shopping and found some great outfits for spring.
_________________________

Sir can you explain me, why we not use "on yesterday"?

Kothow

[Yankee]

Hi

You do not need a prepostion with words such as yesterday, today, tomorrow, this morning, etc.

You use the prepostion on when you talk about a specific date or day such as:
Tuesday, June 13th, New Year's Day, etc.

Amy