In an A2 test the correct answer to "She cries on purpose" was "Elle fait exprès de pleurer". Could "Elle pleure exprès" also be correct ?

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.

Thanks for your reply Michael. I think ‘exprès’ can be used by itself, but I have just asked the question again in a better way to see if a french speaker can confirm this.