hi,luschan,difference between substantial and concrete

HI luschan, I am very confused between two words, i used the dictionary but I am still confused.
what is synonymous for the word concrete evidence.
1.particular evidence’
2.specific evidence
3.substantial evidence.
I saw this question in toefl practice test
looking forward your help.

I am sorry, but this question seems confusing to me too. Here is a definition I found for “concrete” : 1. Of or relating to an actual, specific thing or instance; particular: ex: had the concrete evidence needed to convict.

So it seems like specific or particular would both work. Actually, when I first read the question I thought the answer was “substantial evidence” because substantial implies it is real. Hopefully someone with more expertise will chime in.

concrete evidence = specific evidence. (based on facts, not on ideas or supposition)

The options would have included ‘material evidence’ as well. In law, ‘concrete evidence’ is taken to mean, mostly, ‘material evidence’, which is usually physical, tangible or conspicuous. They are also referred to as exhibits.

It is not necessarily the case that the options should include ‘material evidence’ and it seems from the question that in this case, it didn’t… which is just as well or the question would have been flawed.