Place chicken broth, mushrooms and bamboo shoots in saucepan. Bring to boil, reduce heat and simmer 5 minutes. Add scallops, soy sauce and pepper. Bring to a boil. Add corn starch mixture and stir a few seconds until thickened. Stir briskly with a chop stick and gradually pour in egg. Remove from heat. Stir in vinegar; sprinkle with green onion. Serve immediately.
