1.
The hole in the ozone layer was discovered over Antarctica almost thirty years ago.
大约30年以前，南极上空的臭氧层上发现有空洞。
2.
"About three years ago," said Carrie.
“大约三年以前，"嘉莉说，
3.
"Pewter dates Back at least 2,000 years, to Roman times. Ancient pewter contained about 70% tin and 30% lead."
"白镴可以追溯到最少2,000年前的罗马时代。古代白镴大约含有70%锡和30%铅。"
4.
About 2500 years ago there was a very long war.
大约2500年以前，有一场旷日持久的战争。
5.
The Great Pyramid was built nearly five thousand years ago for a king Called Khufu.
大金字塔是在大约5000年以前为胡夫国王建筑的。
6.
It's about eight thirty
大约是8 点30 分。
7.
INDICATIONS THAT the West Antarctic ice sheet might be in the midst of a vanishing act first began cropping up about30 years ago.
在大约30年前，科学家首度指出南极洲西部的冰原可能正处于缩减状态。
8.
As a result, major lunar eruptions of basalt, the most common volcanic rock, ceased nearly three billion years ago.
因此在约30亿年前，月球上大多数的玄武岩岩浆（最常见的火山岩）喷发就已经停止了。
9.
Primitive men lived in China aBout 1.7 million years ago.
大约170 万年以前就有原始人居住在中国。
10.
I became Mr. Green's secretary nearly three years ago.
大约三年以前我当上了格林先生的秘书。
11.
This clam fossil is from the Cretaceous Period, approximately 100 million years ago.
这个蛤化石来自大约一亿年以前的白垩纪时期.
12.
The chosen consumption per head must be multiplied by the estimated population at the date for which the supply is being planned, some thirty years ahead or more.
所选定的每人用水量必须乘以今后大约30年或更长时间后的计划供水的估算人口数。
13.
It was invented about two thousand years ago .
大约两千年前发明的。
14.
Yes. About four years ago.
是的 ，大约四年前走的。
15.
It's our annual sales conference and there will be about 30 people involved.
这是我们每年的营销会议，大约有30人参加。
16.
A Study on Mao Poetry: the Preface During the Reform and Opening-Up 30 Years;
改革开放30年以来的《毛诗·大序》研究
17.
But there were no horses in this country until the Spanish brought them here about 400 years ago.
但是直到大约400年前西班牙人带马到这儿以前，这个国家没有马。
18.
gracile hominid of southern Africa; from about 3 million years ago; formerly Plesianthropus_transvaalensis.
非洲南部体形纤弱的原始人；大约三百万年前；以前的迩人。