List all the trips that you have taken outside of the U.S since becoming a lawful permanent resident . I don't remember

Answer to the best of your knowledge. Include a separate page with your N400 that explains the situation. For instance, you could write...I traveled to Canada 3 times in the Summer of 2010 each time was for about 2 nights. I do not remember the exact dates. Andre Olivie Seattle Immigration Attorney www.olivielaw.com www.olivielaw.com

Use your passport/s to refresh your memory.

You've been given excellent advice by my esteemed colleagues. Yes, look over your passport to figure out when the exit/entry stamps occurred to refresh your memory, look in your documents and e-mails for any travel itineraries, electronic ticket copies, receipts and bills to help you figure out the timeline. As mentioned already, you can provide a big picture - i.e. the approximate dates - but if the absence was longer than 6 months, this can create a problem so in that case it would be good to confer with an immigration attorney for advice on how to report such an absence without triggering a presumption in immigration officials that you may have abandoned your permanent residency status. Also, the longer the absence, the more exact I'd try to be on the dates/times, and of course, you want to list the places (countries) precisely. If you do make errors, the most likely outcome will be that you will receive an RFE from immigration officials inquiring about specific dates of your absences, and at that time you can still try to figure out the exact times and dates but will then have to provide evidence. It is always best to avoid such situations, however, and to answer as precisely as you can be from the start. If you need assistance, consult with an immigration attorney in your area - perhaps someone could simply sit down with you and help you fill out the form, which couldn't be too difficult or costly but could save you a lot of headaches down the road. My office is not far from Moline if you would like me to help, or I can certainly refer you to an immigration attorney in the area if you'd like.