Rivaling the pyramids of Egypt or even the ancient cities of the Maya as an achievement, the army of terra-cotta warriors created to protect Qin Shi Huang, China’s first emperor, in his afterlife is more than 2,000 years old and took 700,000 artisans more than 36 years to complete them.

1. took 700,000 artisans more than 36 years to complete them
2. took 700,000 artisans more than 36 years to complete it

3. took 700,000 artisans more than 36 years to complete

4. 700,000 artisans took more than 36 years to complete
5. to complete them too 700,000 artisans more than 36 years

答案是B，为什么不C不行，为什么还要个it在句尾？？？

我不太明白，如果是It is difficult to complete的话呢？

要说It is difficult to complete it?

原句是说  兵马俑 took sb. (some time) to complete

一定要说  兵马俑 took sb. (some time) to complete it 的话

it 不就是指代兵马俑吗？