Abacuses are so fast that people use them today保持句意
问题描述：
Abacuses are so fast that people use them today保持句意
Abacuses are —— —— —— people to use today
答
保持句意：Abacuses are —fast— —enough— —for— people to use today.对了给你分帮我再解一下这题3 multiplied by5 equals 15 划线提问15划线 —— —— ——3 —— by 5 ——？