Replacing a conjunction can change the relation between the participants and the event. The table summarizes the effects described in this passage.
ParticleMain contextual contribution
وJoint participation; no required order
فOrder and close sequence
ثمOrder with an interval
لاExcluding the second from the predicate
بلCorrection or transition to the second
أوAlternative or uncertainty according to context
Principle: no one particle is always rhetorically superior. Its suitability follows the intended truth conditions and the listener's need for clarification.