Last Sunday I went to visit the History Museum where I saw a pot about 1 000 years before

问题补充：

Last Sunday I went to visit the History Museum where I saw a pot about 1,000 years before.

A. so it had been

B. so had it been

C. what it had been

D. as it had been

答案：

A. so it had been

B. so had it been

C. what it had been

(答案→)D. as it had been

解析：句意：上周日，我去了参观历史博物馆，我看见了一个正如一千年以前一样的锅。as引导定语从句，在句中作为定语从句的宾语，可意为“正如”，故选D