Asian markets and noodle vendors in the U.S. offer numerous varieties of Chinese noodles—including wheat noodles, which were first made some 2,000 years ago; rice noodles, a favorite in southern China; absorbent bean threads; and refined egg noodles. Here's what to do with some standard types.
**Loose nests of soft off-white fresh wheat noodles are sold, refrigerated, in 1-pound bags. Buy no more than two days before using and store in refrigerator. Some sun mian are thin and round; others are broader and flat—more ribbonlike. All must be boiled for about 7 minutes. Add to soups or toss with sauces.
**Stiff off-white dried wheat noodles are sold either in ¾ -pound bags in small swirls, or in long straight bundles. Look in dried noodle section; store in a dry place. Ingredients (wheat flour and salt) are listed on label in English. Noodles must be boiled for about 7 minutes. Add to soups or toss with sauces.
**NEN DZEM FEN
**Short hand-rolled fresh rice noodles, also called silver pin noodles, are sold in 1-pound bags or pouches. Look in refrigerator section, buy up to two days before using, and store in refrigerator. These don't need soaking or boiling—just stir-fry with meats and vegetables until just heated through.
**Folded bundles or blocks of wispy white rice vermicelli are sold in 1-pound packages. Look in dried noodle section. Store in a dry place. These must be soaked in hot water until soft, about 20 minutes. Then add to stir-fries or, after boiling for about 5 seconds, to soups (noodles will cloud soup if not boiled separately).
**SHA HO FEN
**Fresh rice sheets are sold individually or folded, lightly oiled, and layered in 1-pound bags. Look in refrigerator section, buy up to two days before using, and store in refrigerator. Cut as desired (they come precooked) and use as wrappers or in soups: Simply place strands in a bowl and cover with hot broth.
**Brittle white bean threads also called ''green'' bean threads or cellophane noodles (they turn clear when cooked), are tied in 1.8-, 3.5-, and 8.8-ounce bunches. Look in dried noodle section. Store in a dry place. Soak in hot water for about 20 minutes before adding to soups, braised dishes, or dumplings.
**Long yellow fresh egg noodles are sold in 1-pound bags; thinner versions are available as well. Look in refrigerator section, buy up to two days before using, and store in refrigerator. Do not soak or preboil noodles; just add directly to stir-fries or, if using the more delicate thinner noodles, to soups.
**SHI DAN MIAN
**Tangles of fresh egg noodles are sold in 1-pound bags. Look in refrigerator section, buy up to two days before using, and store in refrigerator. They must be boiled for about 5 minutes. Use in stir-fries, soups, or shallow-fried dishes. (For a recipe, see Liang Mian Hwan (''Two Sides Brown'').)