I am curious too, Paul
Some verbs can be "phrasal", meaning that they may or must be followed by a preposition, and when they are followed by a preposition, they have a different meaning. Some verbs are always phrasal and others have phrasal forms.
Like parler. Parler means "to speak"
But <> is a phrasal verb meaning to speak to. <> I am speaking to Jean.
And <> is also a phrasal verb meaning to speak about or speak of. <> We are speaking about this book.
Phrasal verbs are very common in both Anglais et Français, and my profs say to learn them as a whole, with their preposition and their meanings.
Always (I think), when using a phrasal verb, you cannot omit the preposition without changing the meaning or simply being incorrect.
When using a phrasal verb with a pronoun, that is, when you know from the context, the object of the preposition, you replace both the preposition and its object with the pronouns <> or <>.
<> replaces the preposition <<à>> and its object, and the <> replaces the preposition <> and its object. And these pronouns cannot be omitted.
And all this begs the question: can exprès be used by itself or must it always be part of an idiomatic faire expression? And I don't know the answer to this, but I say you posted almost a month ago and no one had responded, so I thought I'd restart the discussion.