"If I wore a white shirt to school, by the end of the day it would be brown, " recalls He, who was born in 1974, "and there would be a ring of black soot under the collar."
他回忆说：“如果我穿一件白衬衫去上学，一天下来衬衫就变成了棕褐色。 领子下面还有一圈黑黑的烟灰。”
2
Several strengthening methods, including stiffened internal ring reinforcement, collar plate reinforcement, internal plate reinforcement and chord thickness reinforcement, are introduced here.