[TxMt] regex question

[Oliver Taylor]

I don't know where else to turn for help with regex, so I turn to  
you. Consider the following:

------------------------
ONCE
(twice)
Three times a lady.
Not as much as the Gambler.
(This sucks)
How would you know?
------------------------

How do I match the 2nd line but not the 5th?
How do I match the 6th, but not he 3rd?

Is this possible?

P.S. Do you guys have any really good references for regex (aside  
from the manuel), where I can hunt down problems like this?