【基础知识】关键词：基数；序数；倍数；分数；大数；约数　　1. 倍数：三种方式—twice as +adj. + as; 　　twice more + adj. + than; 　　twice + the size of 　　①. twice the size of ours 两倍于　　②. twice as large as ours 两倍于　　③. twice larger than...