Sloppy, slanted, and uneven stitching is a sign of a poorly-made, fake bag. Designer bags will always have quality stitching because it is part of the designer's reputation to produce a quality item. Make sure to check the stitching on the inside of the bag too. Some fakes hide their sloppy work in the lining of the bag. If it's a leather bag, it should smell like leather. It should also be pretty heavy. A very light and flimsy bag is probably fake. A real designer bag will be lined, and often with leather. If the bag is lined with a cheap material, or poorly stitched, it's probably fake. The zippers should zip very smoothly, and feel heavy and high-quality. If the zipper pull falls off quickly, the bag's probably fake. Usually the underside of the zipper pull will have a logo. Many handbag manufacturers use the same high quality zipper manufacturer on all of their bags.

===
Write a summary of the previous text in Chinese:
近距离观察车线是否稀松。 检查皮革和内衬的质量。 检查拉链的功能和质量。