A formula derived by the author for calculation of arbitrary threecentered arch type headings was introduced here with some modifications made to the conventional design and calculation methods.
介绍了所推导的任意三心拱巷道计算公式，并修正了拱形巷道传统的设计与计算。
2
Three new companies are testing out a new kind of social network -centered around (mostly) women's fashion.
有三家新公司正在测试一种新型的社会网络——关注女性时尚信息。
3
Most of the research centered on rice, an important crop in those three West African countries.