problem with regex, how to conclude more than one character

[tecspring at gmail.com]

I always have no idea about how to express "conclude the entire word"
with regexp,  while using python, I encountered this problem again...

for example, if I want to match the "string" in "test a string",
re.findall(r"[^a]* (\w+)","test a string") will work, but what if
there is not "a" but "an"(test a string)? the [^an] will failed
because it will stop at the first character "a".

I guess people not always use this kind of way to filter words?
Here comes the real problem I encountered:
I want to filter the text both in "<td>" block and the "<span>"'s
title attribute
###################### code #############################
import re
content='''<tr align="center" valign="middle" class="CellCss"><td
valign="middle">LA</td><td valign="middle">11/10/2008</td><td
valign="middle">1340/1430</td><td valign="middle">PF1/5</td><td
valign="middle"><span title="Understanding the stock market"
class="MouseCursor">Understand....</span></td><td title="Charisma"
valign="middle">Charisma</td><td valign="middle">Booked</td><td
valign="middle">'''

re.findall(r'''<td valign="middle">([^<]+)</td><td
valign="middle">([^<]+)</td><td valign="middle">([^<]+)</td><td
valign="middle">([^<]+)</td><td valign="middle"><span
title="([^"]*)"''',content)

#################### code end ############################
As you saw above,
I get the results with "LA,11/10/2008,1340/1430,PF1/5,Understanding
the stock market"
there are two "<span>" block but I can just get the "title" attribute
of the first "<span>" using regexp.
for the second, which should be "Charisma" I need to use some kind of
[^</td>]* to match "class="MouseCursor">Understand....</span></td>",
then I can continue match the second "<span>" block.

Maybe I didn't describe this clearly, then feel free to tell me:)
thanks for any further reply!