Related:

• Are there those in the land of the brave Who can tell me how I should behave When I am disgraced Because I erased A file I intended to save?
• Doctor: You need glasses. Patient: How did you know?
  Doctor: I could tell as soon as you walked through the window....
• How can they tell?
• You can tell a doctor as far as you can see him, but you can't tell him much.
• How can I tell you I love you when you're sitting on my face?
• How can I tell what I think until I see what I say?
  And how can I say what I think unless someone asks me?...
• Gosh that takes me back... or is it forward? That's the trouble with time travel, you never can tell.
  -- Doctor Who "Androids of Tara...