Is every explanatory apposition a substitute?

The questioner : Like the preservation of the substitute!

The Shaykh : Yes

The questioner : Can the second be explained by the first? Does it fall under the category of substitute?

The Shaykh : No, they call it a substitute.

The questioner : Explanatory apposition.

The Shaykh : They call it a substitute, "Every explanatory apposition is suitable to be a substitute", this is a rule.

The questioner : Synonymous.

The Shaykh : Synonymous, yes, except in specific issues where they made exceptions, yes. For this reason, Ibn Malik said regarding explanatory apposition:
"And suitable for being a substitute it is seen *** in other than the case of 'O boy, Ya'mur'"
Only two issues, yes.