Source: A particle along with a verb in a phrasal verb forms a single semantic unit. Particles affect the meaning of the phrasal verb. Prepositions do not change the meanings of their preceding verbs and are independent of them.
pp 108-110 of Plain Words, 2014, by Gowers censures
'verbosity in phrasal verbs'. I want to avoid redundant particles, but how do I determine if a particle's genuinely mandatory?
Please answer in general, and NOT only for the following examples:
1. Does expound need on after? Some of ODO's example sentences use on, but others not.
2. Must jar always be followed by with? This motivated this example.
Suppose that person H thinks farro Healthy, but N thinks it Noxious.
I know that the following's perfectly right: 3. H jars with N. But why not: 4. H and N jar. ?