(on) these day?

[Belly T]

Although our country does not have an offical day to celebrate our mother and father, we keep sending cards (on) those day...

My bold above, do we need to add "On" before "those day" or not?

[Casiopea]

Yes, you need on in that context.

Test1: When? On those days. <adverbial phrase>
Test2: What? Those days. <noun phrase>

Those days doesn't function as the object, either direct or indirect, of the verb sending. It functions as the object of a prepositional phrase. That's why on, the head of that phrase, is needed.

All the best.

[Belly T]

But why we can say " Flowers bloom these days"? But not " He's very busy on these day"?

[Casiopea]

Reference is the answer. Below, the [a] examples with on, tell us the speaker is, say, pointing to a calendar. These days could be next week, last week or even next month or next year. In the [b] examples, however, the speaker is making reference to the present.

[1a] Flowers bloom on these days (here). <demonstrative pronoun>
[1b] Flowers bloom these days. <nominal adverb>

[2a] He's very busy these days. <nominal adverb>
[2b] He's very busy on these days (here). <demonstrative pronoun>

We keep sending cards on those days: the unoffical days during the year. Not these days now, at the present time.

All the best.

[Belly T]

So, Casiopea, these days is unidentified but On these days is a indetified one?
And if we use "Those days", the usage is the same as "these days"? And you meant the time we sending cards to our parents (or the day we celebrate Mother or father day) is indentified anually?

[Casiopea]

Both are (to use your term) "identified". The difference is that one is present, the other not.

(On) these days (now, a present continuum of time)
On those days (then, a past or future continuum of time)

Ex: We keep sending cards these days. (Now, present)
Ex: We keep sending cards on those days. (Then, past or future)

All the best.

[Belly T]

Excuse me, but I'm in trouble with " these days" and" On these days", " those days" and "on those days"
"These days" describe the present ?
And 'those days" are describe the days that you pointed on the calendar, right?
So, how about " those days" and "on those days"?

[Casiopea]

Let's get the deictics out of the way, first. Those refers to things away from the speaker in time and/or space. So, in the examples we're dealing with, those refers either to days gone by or to days yet to come. These refers to things near the speaker in time and/or space. So, in our examples, these refers to a continuum of days at the present time.

Now, given the deictics and looking back at your example sentence, you could use either on these days or on those days:

Ex: Although our country does not have an offical day to celebrate our mother and father, we keep sending cards on those day...
=> on those days (then, at that time of year)

Ex: Although our country does not have an offical day to celebrate our mother and father, we keep sending cards on these day...
=> on these days (now, the days I am referring to in the sentence)

Does that help?

All the best.

[Belly T]

After all it's clear to me between " on these days" and "on those days", so how about the rest" Those days (only- not on)" and "These đays (only- not on)" ?

[Dr. Jamshid Ibrahim]

Reference is the answer. Below, the [a] examples with on, tell us the speaker is, say, pointing to a calendar. These days could be next week, last week or even next month or next year. In the [b] examples, however, the speaker is making reference to the present.

[1a] Flowers bloom on these days (here). <demonstrative pronoun>
[1b] Flowers bloom these days. <nominal adverb>

[2a] He's very busy these days. <nominal adverb>
[2b] He's very busy on these days (here). <demonstrative pronoun>

We keep sending cards on those days: the unoffical days during the year. Not these days now, at the present time.

All the best.

A very interesting topic. Your explanations are perfect Casiopea but saying that these days can refer to the past (which is away from the speaker) is confusing.