请教几道语法题

1 The capital of the United States, originally New York City, was moved to Philadephia where stayed until 1800。

为什么B是对的呢？

2. The chorus plays a large part in any oratorio, linking areas were sung by soloists with segments of choral music.

如果把D中的were去掉，那么逗号后的部分作前面的什么成分呢？

3. As the late 1940's, J.Pollock's art has been considered the pivatal manifestation of Abstract Expressionism, as his form of it is known.

在of后可以直接跟it is known?

1 originally做的是状语，不是定语

2 应该是were错了吧，linking的主语是chorus，动名词短句的意思相当于一个定语从句，which link...

3 as (his form of it) is known，这样读吧

第二个，感觉应该是补语……（对不起，本人对语法成分分类并不在行，但是这个句子明显不是个定语从句），linking后面的句子是补充说明前一句chorus的重要地位。

其他两个同意楼上意见^_^