5个数字3个为一组有多少组

简介：As the author of Tiangong Kaiwu, Song Yingxing had very high attainments in agriculture. He had long known that potatoes, corn, and sweet potatoes were more suitable for farming in the north. However, he was only a petty official at first and had resigned, so he did not have the right to submit a memorial. And even if he did, no one would pay attention to him, so there was nothing he could do in his hurry.