Assume

1) What is the difference between:
Assume,presume,suppose
I think "suppose" implies about thoughs more than the others.
Please tell me what do you think {2)In slang I sometimes hear the "do" like in this sentence obviated. Is the "do" essential here?}

Thanks

I can't catch on to the difference between "suppose" and "presume", can put a few examples please? A dictionary I fould I net. says: suppose = presume to be true. Is it relevant?
Thanks and another auestion: which one is correct:
1) Nobody knows who was he.
1) Nobody knows who he was.

I know that it's a stupid question but I am confused

Use subject-verb inversion and do-support with main clauses which ask questions (unless questioning the subject, of course).
Do not use inversion with the corresponding subordinate clauses (indirect questions).

Who was he? / Nobody knows who he was.
What did you put on the shelf? / I don't know what you put on the shelf.
Where has he gone? / I'll bet you can't guess where he has gone.
What is the difference between these methods? / I can see that you have no idea what the difference is between these methods.
Why did he leave everything on the table? / We were unable to determine why he left everything on the table.
Are you concerned that you won't pass the test? / I wonder if you are concerned that you won't pass the test. [Note the addition of "if" when transforming a yes-no question to an indirect question structure.]
When will the documents be ready? / In our office there is complete confusion about when the documents will be ready.
Can you see it? / I have no idea whether you can see it. [Note "whether", which can substitute for "if" in these constructions.]
How much was that package of ribbons? / The clerk had to find out how much that package of ribbons was.

In my experience what bothers learners most about these patterns is a form of the verb "to be" left at the end of the sentence. I don't know why. It is correct!

I don't know [what the problem is / where John was / who the strangers were / how much it is ].

All three correct!

(I'm sure you meant "who they were" on the last line.)

It's a bit more idiomatic to ask (first sentence) "Does anyone know who ..."

Good work.

1# Who were the burglars?
2# Does anyone know who the burglars were?

What is the grammatical rules for the structure of these sentences. I mean when I say "who are you" and (the incorrect form) "who you are". So in which cases the verb be (are\is\was\whatever) comes after the noun and in which before?
thank you