"That night he could not sleep. He lay awake thinking of the Junkers 88's and of the hardness of the water. He could think of nothing else. They were JU-88's, he said to himself. I know they were. And yet it is not possible, because they would not be flying around so low over here in broad daylight. I know that it is true, and yet I know that it is impossible. Perhaps I am ill. Perhaps I am behaving like a fool and do not know what I am doing or saying. Perhaps I am delirious. For a long time he lay awake thinking these things, and once he sat up in bed and said aloud, "I will prove that I am not crazy. I will make a little speech about something complicated and intellectual. I will talk about what to do with Germany after the war." But before he had time to begin, he was asleep."Which words from the paragraph indicate that the pilot is beginning to doubt that he is recuperating?