酷暑散去,天气渐凉。吃过晚饭,我到朋友家小坐。朋友住的是楼房,窗明几净,空气清新。在我们喝茶的间隙,朋友起身将向光的窗户的纱窗打开,把室内的灯暂时全关了。我赶紧劝阻说,这秋天还没来临,你就不怕屋外的蚊子全飞到你屋子里来吗?朋友微微一笑,说,这你就错了,蚊蝇都有趋光性, Heat to disperse, the weather getting cooler. After dinner, I sat down to a friend’s house. Friends live in the building, the window a few clean, fresh air. In the gap between us drinking tea, a friend got up and opened the window to the window of light and temporarily closed the interior light. I quickly discouraged said that this autumn has not yet come, you are not afraid of all the mosquitoes flying outside your house come? Friends smiled, saying that you are wrong, mosquitoes have phototaxis,