About three decades ago, China was known as the "bicycle kingdom".

大约30年前，中国被称为“自行车王国”。

youdao

In the early spring three decades ago, Mount St. Helens began to rumble.

在三十年前的早春，圣海伦斯山开始轰鸣。

youdao

But in the early spring three decades ago, Mount St. Helens began to rumble.

但是在三十前的春天早些时候，圣海伦火山开始隆隆作响。

youdao

People in developing countries today are consuming nearly twice as much milk, more than three times as much meat and five times as many eggs as they did five decades ago, according to the FAO report.

VOA: standard.2010.02.22

Efficient markets" is a theory about-- well it came in about three decades ago, maybe it's closer to four decades ago-- it's a theory that financial markets work very well and incorporate information very well.

有效市场是...,大约三十年前,甚至四十年前,有人提出了这一假说,他认为金融市场运行良好,而且信息披露全透明

耶鲁公开课 - 金融市场课程节选

But the office that is now his looks the same today as it did three decades ago.

NPR: The Moscone-Milk Anniversary �� And Legacy

Until they came under antitrust attack three decades ago, they had rules forbidding discounts for cash.

FORBES

Transportation burns up 58% of oil supplies--1.9 billion tons--against 42%--905.6 million tons--three decades ago.

FORBES: Magazine Article