垄断竞争的长期均衡点是在平均成本最低点的左侧，为什么厂商越少平均成本越低呢？？求指教~
In a monopolistically competitive market,however, the demand curve is downward sloping,so the zero-profit point is to the left of minimum average cost.This excess capacity is inefficient because average cost would be lower with fewer firms.