Q17:

The steel industry has changed radically over the last two decades, as large, integrated companies such as Bethlehem Steel once conducted operations from mining at one end of the process to shipping at the other have greatly downsized, or in some cases shut down altogether.

1. as large, integrated companies such as Bethlehem Steel

2. as large, integrated companies, such as Bethlehem Steel, that

3. with large, integrated companies, such as Bethlehem Steel, that

4. while large, integrated companies, such as Bethlehem Steel, that

5. and large, integrated companies such as Bethlehem Steel

answer b

我觉得应该选a啊，as引导一个主谓结构的从句啊，为什么要在主语和谓语之间加上that呢？

请教各位nn

The steel industry has changed radically,  as large, integrated companies that once conducted operations have greatly downsized, or in some cases shut down altogether.

因为有conducted这个动词呀。

我还是没有弄明白，对不起，

比如，I like you as mike likes me.

显然是不需要说，I like you as mikes that likes me.

那在什么时候需要加that 呢？

谢谢