Duplicate content concern

I have advice on a particular subject that's split into 6 parts, i.e.
"advice Part 1.html, advice part 2.html etc. But because anyone could
land on any of these pages from a search query out of sequence, I need
the first couple of paragraphs of each page to stipulate certain
safety-related advice and warnings.

Would Google (and other SE's) have a problem with 6 or more pages,
with the same opening 2 paragraphs on each? Would it be intelligent
enough to see the unique content in the rest of these pages or could
it just read the first 2 paragraphs and decide they were duplicate
content?

Also, I have 2 other sites based on different subjects that are
closely themed with my first site. Would some pages on the 3 sites,
containing virtually the same content - but with the topic's name
replaced - be considered duplicate content? The sites are all
justifiably separate entities.

(e.g , "the best way to move a widget" - "the best way to move
something-that's-not-a- widget" and, "widgets need greasing regularly"
- "something-that's-not-a- widget needs greasing regularly")

In case it sounds confusing, my sites are all about different
appliances.

--

Free washing machine help and advice.

www.washerhelp.co.uk

www.xyzed.co.uk/newsgroups/top-posting.html