With sharp knife, slice round steaks very thin, cutting across the grain.
Peel and slice onions and mushrooms.
Cut celery into 1 inch lengths.
Chop spinach coarsely.
Cut scallions in half, lengthwise, leaving about 2 inches of green on top.
Heat oil in heavy skillet and add meat. Cover and cook over low heat until tender but not browned.
Add onions, mushrooms, celery, spinach, scallions and bamboo shoots. Cover and simmer for 5 minutes, stirring several times.
Combine water, bouillon cube, soy sauce and sugar. Mix well and add to meat and vegetables.
Continue cooking for 15 minutes.
Serve over rice