The confusion by English expressions
Does the expression"an arm of,an ocean of,a sea of,a multitude of,many,if not most"have the same meaning with"many"?
And if the expression"flood/swarm/slice/pour attention into"means the same to "pay attention to"?

Question

The confusion by English expressions
   Does the expression"an arm of,an ocean of,a sea of,a multitude of,many,if not most"have the same meaning with"many"? 
   And if the expression"flood/swarm/slice/pour attention into"means the same to "pay attention to"?

Answer

Thanks everyone.

Answer

Does the expression"an arm of,an ocean of,a sea of,a multitude of,many,if not most"have the same meaning as "many"?  Yes

And  does the expression"flood/swarm/slice/pour attention into" mean the same to "pay attention to"?  No. It means  overwhelm/overrun or swamp or invade

Answer

You have to think figuratively. The problem seems to be that you're expecting a literal explanation.

For example, "as soon as we set up our picnic, an army of birds appeared". The idea here is that the many birds were LIKE an army, and would probably "invade" your picnic.

Answer

Thanks all.I think some material books have misleading me

Answer

No, they don't have the same meaning.
Have you tried a dictionary?