Write the next sentence in the following story.

How to cook vegetarian pasta
Heat the oven to 450 f (230 c).
It takes a while for ovens to reach this high temperature, so get it preheating while you are preparing the vegetables.
Mix the vegetables.
Combine the mushrooms, broccoli, spinach, pepper and onion in a large bowl. Sprinkle 1 tablespoon (15ml) of the olive oil over the vegetables and mix well to make sure everything is coated.