Q20:Construction of the Roman Colosseum, which was officially known as the Flavian Amphitheater, began in A.D. 69, during the reign of Vespasian, was completed a decade later, during the reign of Titus, who opened the Colosseum with a one-hundred-day cycle of religious pageants, gladiatorial games, and spectacles.

A.which was officially known as the Flavian Amphitheater, began in A.D. 69, during the reign of Vespasian,

B.officially known as the Flavian Amphitheater, begun in A.D. 69, during the reign of Vespasian, and

C.which was officially known as the Flavian Amphitheater, began in A.D. 69, during the reign of Vespasian, and

D.officially known as the Flavian Amphitheater and begun in A.D. 69, during the reign of Vespasian it

E.officially known as the Flavian Amphitheater, which was begun in A.D. 69, during the reign of Vespasian, and  

the answer is C,but B seems reasonable

B肯定是不对的

首先B使用了begun而不是began，这是一个过去分词，过去分词是不能单独作谓语的，也就是说在and之前 这些语素不能构成一个完整的主谓结构 那么and 就多余了，因为and后面是有谓语的

其次，即便使用的是began，这句话也有问题，对比C which was的存在表明了 officially known as...一定做定语， 但是如果没有which was则这个结构可以向前做定语，也可以向后做状语，会引起歧义

B的begun不好，过去分词做修饰的话，and之前只有主语，没有谓语动词了

Construction of the Roman Colosseum，【officially known as the Flavian Amphitheater】修饰

【Roman Colosseum, begun in A.D. 69】过去分词修饰Construction, 【during the reign of

Vespasian】状语,and+谓语

这个结构里，and之前没有谓语动词，只有主语

Cbegan是过去式，作为动词

结构 Construction of the Roman Colosseum。。。。began。。。and was  completed ...

其次，即便使用的是began，这句话也有问题，对比C which was的存在表明了 officially known as...一定做定语， 但是如果没有which was则这个结构可以向前做定语，也可以向后做状语，会引起歧义

我晕.. 看来我前面的帖子都白回了

大家有没有想这题中同谓语和which从句的区别？

我的理解是，which这里指代the Roman Colosseum，根据which的指代原则（就近和

逻辑意思）很清楚。

而B中同谓语officially known as the Flavian Amphitheater只能修饰逗号前主语

construction,错

open to discuss