Fettucine with Lemon Garlic Shrimp
1 package (9-oz.) Fettuccine 3 tablespoons butter or margarine 1/4 cup chopped onion 4 cloves garlic, chopped 1 can (14.5-oz.) chicken broth 2 tablespoons cornstarch 1 pound medium shrimp, peeled , deveined 1/4 cup chopped fresh parsley 3 tablespoons fresh lemon juice...