问答题 Just outside its wooded headquarters campus, McDonald's Corp. is offering sneak previews of its fast-food future. Now playing at its new flagship restaurant: Digital-media kiosks for burning CDs, downloading cell-phone ring tones and printing photos. Dozens of plasma-screen TVs. Wi-Fi Internet access. New chicken sandwiches. Double-lane drivethrus. And an adjoining McCafe with gourmet coffees, fancy pastries and a fireplace. Coming soon: Other menu items and concepts not yet released to a general audience. Don't expect Starbucks-like makeovers like this one at the 13,600 U. S. McDonald's, or 30,000-plus worldwide; the Oak Brook restaurant, which opened late last month, doubles as public restaurant and test site. But the world's largest restaurant chain is tinkering with various possibilities in technology and design to try to ensure it is a hangout of choice in the future. McDonald's has undergone an image change in more ways than one since a time 2 1/2 years ago when its sales and reputation were sagging amid complaints about its service and food. Despite inconsistent results in some large European countries, that McSlump is no longer: Same-store sales have increased for 25 straight months in the key U. S. market.