After all the criticizing I received, it's pointless to post my timeline now, important is that travelling occured after N-400 was sent, I had 4 years physical presence prior to travelling, I had my reentry permit in front of the IO, didn't want to see it... got approved.
The point to providing your timeline is to clear up some confusion in what you previously posted.
-In October 2008 you mentioned you had 2 long trips (one of 11 months and one of 9 months).You later had you mentioned that these trips occurred during the time you applied, and that you didn't disclose them at interview, but that you provided passport and travel documents (which would have listed trips). In another post you mentioned the 11 month trip was before you applied.
-You also mentioned that you had 3 years 11 months of continuous living in US since you got GC. (You must have meant 3 years 11 months of
physical presence since you got GC, because 5 years of continuous residency is required up until your oath.
-You also mentioned you declared a 2 month trip between interview and oath, and also a 2 month trip on application.
If you mentioned your case in a timeline fashion with all the facts it would resolve alot of confusion, and save people from reacting to only one fact you post.
.. travelling after N-400 was sent (and not disclosed) is NOT a crime, neither a fraud; even if breaking continuous residency, is not 100% automatic denial, it depends on the IO if he/she wants to approve you.
You previously mentioned you provided the travel documents and passport at your interview. But you also mentioned you didn't declare a 11 month trip on your application, eventhough it asks you to declare all trips.
If you didn't declare a trip that shows a presumption in break of continuous residency, don't go preaching to others that it's ok not to disclose such trips on the basis of your approval. For example, if someone took a 13 month trip (that automatically breaks continuous residency), according to your advice it's ok not to disclose it. Likewise, if someone took a 9 month trip to work for a foreign company that it's ok not to disclose such a trip. That's just terrible advice.
Again, after reading all your posts I can only conclude that the IO saw all the trips on the USCIS system and/or travel documents (reentry permit/passport) and concluded that they didn't break continuous residency since you were in studying in a US university abroad.
However, your posts suggest it's ok not to disclose trips since it really depends on the IO if they want to approve you or not, and that there's nothing wrong with it since you got approved. That is simply bad advice and a generalization based on your own circumstance.
Btw, your posts suggest this timeline:
March 2008 applied for GC
June 2008 received reentry permit while out of country
late November -early December 2008 Had interview, passed.
End Feb-early March 2009 Had oath, declared 2 month trip between interview and oath