These are matrices that may be intersected.这是一些能分割的矩阵。This combination process is called the assemblage of stiffness matrices.这种组合的过程称为刚度矩阵的装配.This can be extended to n X n tridiagonal matrices.这可以推广到nXn三对角线的矩阵....
我二十岁前后那几年过得真苦啊。My late teens and early twenties were really rough years.显然，莫扎特在二十几岁到三十刚出头时，身体非常好。Mozart clearly enjoyed good health throughout his twenties and early thirties.结婚二十年里，他只像样地度过两次假。In twenty years of mar-riag...