Preheat oven to 350°F.
Lightly oil a 13-by-9-inch baking pan.
Cook sausage in a large skillet over medium heat, breaking up sausage with side of a spoon, until cooked through, about 10 minutes.
Using a slotted spoon, transfer sausage to a bowl, discarding fat in skillet. Set aside.
Bring a large pot of water to a boil over high heat. Add salt to taste.
Trim lasagna sheets to fit baking pan, if necessary.
Add lasagna sheets to the boiling water, one at a time, stirring gently to keep sheets from sticking to each other. Cook just until al dente, about 2 minutes (water does not have to return to a boil). Drain and rinse under cold running water. Separate and toss lasagna sheets with 2 tablespoons of oil to discourage sticking.
Set aside 1/2 cup of Romano cheese for topping.
Spread 3/4 cup Pomodoro sauce on bottom of baking dish.
Top with 1 lasagna sheet.
Sprinkle with 1/4 each of mozzarella, Parmesan and sausage.
Dot with 1/4 of ricotta.
Top with 3/4 cup Pomodoro sauce.
Repeat three times with 3 more sheets, mozzarella, Parmesan, sausage, ricotta and Pomodoro sauce.
Top with final lasagna sheet, 1 cup Pomodoro sauce and reserved Parmesan cheese. Reserve remaining Pomodoro sauce.
Cover lasagna loosely with aluminum foil. (Lasagna and sauce can be prepared up to here, covered, and refrigerated, up to 1 day ahead.)
Place baking dish on a rimmed baking sheet. Place in preheated oven and bake for 45 minutes.
Uncover and bake until lasagna is bubbling, about 30 minutes more.
Remove from oven and let stand for 15 minutes before serving.
To serve, reheat remaining Pomodoro sauce.
Cut lasagna into 9 portions. Transfer each to a dinner plate.
Top with warm Pomodoro sauce.
Sprinkle with Romano and parsley.