answer: #Person1# asks Miss Smith about the time difference between here and Houston.
documents: #Person1#: Miss Smith, I told Dr. Brown that I would call him in the Houston office at ten o'clock by their time. Please find out the time difference for me so that I'll know when to place the call.
  #Person2#: It's two hours earlier in Houston, sir. I know without looking it up because my sister lives there.