Analysis: A lamp is hung between every two lanterns, and the distance between the two lamps is two meters, so the lamps are hung at both ends of the corridor, but the lanterns are not. The distance between the lamps is 1 m, and the lanterns are hung at both ends of the corridor 1 m, so the total length of lanterns is 80-2=78 meters, and the number of lanterns hanging in the corridor is: (8438. Hang one lantern between every two of the 40 lanterns, which can be hung (40-2)÷2=38÷2= 19 (lamp), and two lanterns at both ends, *** 19+2=2 1 (lamp).

Solution: The number of lanterns hanging in the corridor is: (80-2) ÷ 2+1= 78 ÷ 2+1= 39+1= 40 (pieces).

The number of hanging lamps in the corridor is: (40-2) ÷ 2+2 = 38 ÷ 2+2 =19+2 = 21(lamps).

Answer: 2 1 lamp is required.