_____ in thought, he sat at the edge of the bed, with his eyes _____ on the letter in his hand.

---Would you please show me ___ to run the machine?----Sure.

 The policeman kept his eyes________on the screen of the computer to identify the criminal's footprints.

 The old couple, ________ in the small village for years, can tell the names of all the villagers.

The temple , _______ the Song Dynasty ,was pulled down last month.