xiaoerhei, I think either way is fine. Usually, you can just fill in your last position and last location with the full date range. However, if there is a significant change in location (say from China to U.S.) or position (say from marketing to finance), even it's within the same company, you may want to put into two entries.
The Kellogg newpaper is called Merger. At Kellogg, there are lots of opportunities to do community service. You can check the SEEK program and club to see some of them.