Tim got in trouble for forgetting his maths copy.

Thus Mercury cures the holes which it has provoked and other Arsenicals do likewise.

I suppose I may have leave to do that! Yes, she could do that, he said, but there was no road to that place; it lay east of the sun and west of the moon, and she could never find her way there.

Trial and error was a big part of the process: We need to fail down here so we don't fail up there, [Neil] Armstrong insists, though even some of the mistakes and malfunctions at ground level cause devastating casualties.