1. date back to 追溯到， 后接点时间，在句中做谓语时， 常用一般现在时， 无被动态。＝ date from
date back 意为“追溯; 存在”， 后接“段时间”
eg. The Great Wall of China dates back to the third century B.C.
The beautiful folk legend dates back more than 300 years.
2. scale
n. 1)磅秤；天平盘
a pair of scales 一台天平
a spring scale 弹簧秤
weigh sth. In the scale 用秤称
