signal
n.信号;标志 v.发信号;标志著 a.显著的
The headmaster gave the signal to begin.校长示意开始。
significance
n.意义，含义;重要性，重大
Stella didn’t attach any significance to Doug’s query.斯特拉并不重视道格提出的问题。
significant
a.相当数量的;意义重大的;意味深长的
His most significant political achievement was the abolition of the death penalty.他政治上的最大成就是废除了死刑。
simplicity
n.简单，简易;朴素
Mona wrote with a beautiful simplicity of style.莫娜的文笔朴实优美。
simplify
vt.简化，使简明
an attempt to simplify the tax system简化税制的尝试
