...that's probably it

[shootingstar]

Mrs. Webb:
George, you know 's well as I do: the groom can't see his bride on his wedding day. not until he sees her in church.
George:
Aw! - that's just a superstition. - Good morning Mr. Webb.
.......
Mrs. Webb:
Millions have folla'd it, George, and you don't want to be the first to fly in the face of custom.
......
Mr. Webb:
Suddenly and loudly.
Well, George, how are you?
George:
Startled, choking over his coffee.
Oh, fine, I'm fine.
Pause.
Mr. Webb, what sense could there be in a superstition like that?
Mr. Webb:
Well, you see, - on her wedding morning, a girl's head's apt to be full of ... clothes and one thing and another. Don't you think that's probably it?
George:
Ye-e-s. I never thought of that.
Mr. Webb:
A girl's apt to be a mite nervous on her wedding day.
(Thornton Wilder, Our Town)

Hello,
I think a that can be added here:: Don't you think that that is probably it? - or am I wrong? Please, what is the meaning of that's probably it here?

 

[5jj]

I think a that can be added here:: Don't you think that that is probably it? - or am I wrong?

You are right.

Please, what is the meaning of that's probably it here?

That is probably the reason.

 

[Barque]

I think a that can be added here:: Don't you think that that is probably it? - or am I wrong?

It can be added but it also works without it. It's normal to omit "that" in structures like that.

 

[shootingstar]

It can be added but it also works without it. It's normal to omit "that" in structures like that.

Yes, thank you, I know but I wasn't sure of the meaning without the second that. So I added the second that to clarify this issue.

 

[Barque]

So i added the second that to clarify this issue.

You added the first "that". That's the optional one.

The second "that" (part of "that's" in the quoted text) was the one that was already there.

 

[shootingstar]

Agreed. My point of view was that I just added a second or another that no matter in which order.