In a samll saucepan bring broth and broccoli to boil. Reduce heat; cover and simmer for 5 minutes. Do not drain. Set aside. In a large saucepan cook mushrooms and onions in margarine till tender. Stir in flour, salt, and pepper. Add milk all at once. Cook and stir till bubbly. Cook and stir 1 minute more. Stir in broccoli with broth, corn, and pimiento; heat through. BETTER HOMES AND GARDENS