Which sentence in this excerpt from "In Another Country" by Ernest Hemingway is an example of irony?
My knee did not bend and the leg dropped straight from the knee to the ankle without a calf, and the machine was to bend the knee and make it move as riding a tricycle. But it did not bend yet, and instead the machine lurched when it came to the bending part. The doctor said:" That will all pass. You are a fortunate young man. You will play football again like a champion."