The first blow of grief stuns you. You sit (or fall) down. Your mind repeats: she is dead. But there is no meaning to this, nothing in real-time to provide context for the loss.
Nature allows you to lie stunned for a few moments. But then, you must get up. Even if only to your knees. You're thirsty, or the children need a meal, the phone is ringing, someone is delivering flowers, there is class party at school at which you're expected.
And so, despite everything, the first thing you learn about death is: life goes on. The music pauses, perhaps, but then it begins again. And you have this choice. You can lie there, and let the grass grow over you, or you can hobble over to the shed and get the mower out and cut the grass that is still, amazingly, growing.