After John wrote the abstract "介绍了由硅酸盐水泥与铝酸盐水泥组成的二元体系,以及掺石膏后三元体系的凝结时间、力学性能、体积变形等,水化硬化机理和应用方面的国内外研究现状,并提出了今后的研究重点.", he wrote these keywords "二元体系, 混合体系, 三元体系, 硅酸盐水泥". Do you think his choice of keywords was correct? Answer yes or no.
yes