The Xiongnu entered Xinjiang mainly around 176 B.C.

The Space-time Distributing Characteristics of Wars in Guangxi ( 221 B.C.-1911);

广西战争的时空分布特征（前221&1911）

The practice goes so far back in time that an Egyptian painting from 1500 B.C. depicts their use.

欧洲水蛭的具体医疗用法可以从公元前1500年前的埃及壁画中窥见一斑。

The history of the pyramids in Egypt dates back to about 3.000 B.C.

埃及金字塔的历史可以追溯到公元前3000年。

The history of castration can be traced back to 1 100 B.C.

去势术在中国的历史至少可上溯至公元前十一世纪。

All right, now, the Forum came into being in the sixth century B.C.,

古罗马中心广场是公元前6世纪落成的

The concept of "science" has already been used since 7th B.C. As an ancient civilized country.

公元前七世纪已经出现了科学这个概念。

Researchers have revealed that the culture lasted mainly from 4300 B.C. to 2500 B.C.

研究者发现大汶口文化主要从公元前4300年持续到公元前2500年。

The construction of the tomb started in 247 B.C., and it took 36 years to complete.

这座陵墓始建于公元前247年，花费了36年时间才完工。

According to relevant researches, the culture was prosperous from 3300 B.C. to 2050 B.C.

根据相关研究，马家窑文化兴盛的时间为公元前3300年到公元前2050年。

It is known that great wall was bulit in the3rd century B.C.

众所周知，长城是在公元前3世纪建成的。

Although no one's quite sure, some believe that the practice dates back to600 B.C.

虽然不能确定，但是据说该活动可以追溯到公元前600年。

We have entered into an electronic information age from the era B.C. ( before computers).

我们也因电脑而进入电子资讯时期。

For example, Xi'an's history can be traced back to the11th century B.C.

例如，西安的历史可以上溯到公元前11世纪。

The discovery of alcoholic fermentationappears to date back to about 7000 B.C. in China.

在中国酒精发酵的发现原理可追溯到大约公元前7000年前。

The body of one statue was found among remains dating from the fifteenth century B.C.

雕像的躯体是在公元前15世纪的历史文物中发现的。

Glue is an invention; it's been around since 4000 B.C.

因为胶是一项伟大的发明，它早在公元前4000年左右就已经出现了。

Why didn't I go back to school in the B.C. ( before children) era?

我为什么没在孩子出生前重返校园？

It began in 5000 B.C. and lasted about 3000 years.

它开始于公元前5000年，历经了大约3000年。

Paper has been found in Chinese tombs dating to the2nd century B.C.

公元前2世纪的中国古墓中就发现了纸。

like one that was the center of a settlement around 250 B.C.

就像是中央这座大约在公元前250年建造的金字塔。