I wanna discuss the difference between the following two sentences:
- The policy will have mostly negative economic impacts.
- The policy will have negative economic impacts for the most part.
First I am going to correct the English in both sentences
The policy will have a mostly negative economic impact.
The policy will have a negative economic impact for the most part.
In 1., "mostly" modifies negative. So the policy's other impacts, eg political or environmental, are unaddressed.
A1. This is incorrect. What the sentence means is "The policy will have a mainly negative economic influence". It also implies that it will not be totally negative.
In 2., "for the most part" modifies either economic impact or the whole sentence; either way, the sentence basically means the negative economic impact outweighs other impacts.
A2. This is also incorrect. Once again what the sentence means is "The policy will have a mainly negative economic influence" The use of the idiom "for the most part" just means mainly so the answer is as for In 1.
Meaning of Idiom ‘For the Most Part’; For the most part means in general; usually; mostly Ref Idioms Online
mostly adverb; mainly: Ref CED Mostly
impact; to have an influence on something: Ref CED Impact