Cook fettuccine according to package directions; drain well. Set fettuccine aside.
Meanwhile, drain clams, reserving liquid from one of the cans. Add enough half-and-half, light cream, or milk to the reserved liquid to make 1-1/2 cups.
For sauce, in a medium saucepan cook mushrooms, green onions, and garlic in margarine or butter until tender. Stir in flour, basil, oregano, and pepper; add clam juice mixture all at once. Cook and stir until thickened and bubbly. Cook and stir for 1 minute more. Stir in clams, parsley, and the 1/4 cup wine, half-and-half, light cream, or milk; heat through.
Divide fettuccine among four dinner plates. Spoon clam sauce over each. Sprinkle with Parmesan cheese. Garnish with additional fresh basil, if desired. Makes 4 servings.