? Multi-span greenhouse has a land utilization, the greenhouse temperature is more evenly distributed and the change is relatively flat, little difference between the ground temperature, shelf edge with a small proportion of low temperature; shed available for small mechanization, easy to scale management, etc. . ? Multi-span greenhouse greenhouses built from north to south 5 to 7 percent more than what the translucent, light distribution, the greenhouse temperature changes during the day flat. Therefore, use of greenhouses north-south. Late autumn south west 5 ~ 10o, south east early spring can be 5 ~ 10o), namely the North-South extension of East and West sides of the light receiving surface. ??