OG SC23 由官方解释引发的疑惑~求教NN们

林木萧

23 In a previous design, the weight of the discus used in track competition is concentrated in a metal center， but now it is lined with lead around the perimeter, thereby improving stability in flight and resulting in longer throws.

(A)In a previous design, the weight of the discus used in track competition is concentrated in a metal center, but now it is
In a previous design, the weight of the discus used in track competition is concentrated in a metal center, but now it is

(B)According to a previous design, the weight of the discus used in track competition was concentrated in a metal center, but now it is

(C)Once designed with its weight concentrated in a metal center, the discus used in track competition is now

(D)The discus used in track competition, once designed with its weight concentrated in a metal center, but now

(E)The discus used in track competition was once designed having its weight concentrated in a metal center and now

答案选对，其他解释基本懂，但是E中“the sentence is missing a main verb in the final phrase”  这句话的意思是 thereby improving stability in flight and resulting in longer throws  缺少动词吗？如果加上动词的话，那就不是伴随状语了，就会前面的句子构成并列？LZ凌乱了，求NN们解释

HarrisZheng

Now 后面要有is 这就是那个动词

liulu007

我也不太清楚OG的解释是什么意思，我怎么都看不出D和E哪里缺少主要动词，我当时选是觉得E当中有and  那么，was once designed  就得和 is now lined 平行，才排除的。同求NN解释D,E。谢谢。

liulu007

又仔细看了遍解释，有点小小的理解。贴上来大家一起讨论下哈。
选项(E)The discus used in track competition was once designed having its weight concentrated in a metal center and now
这道题未画线的部分lined with lead ……应该也是指前面的主语，也就是the discus，那么把它和lined with lead 联系起来，不难发现应该少了一个is这个动词。和选项D是同样的错误。不知道这么理解OG的解释对不对。欢迎找错哦。

HarrisZheng

又仔细看了遍解释，有点小小的理解。贴上来大家一起讨论下哈。
选项(E)The discus used in track competition was once designed having its weight concentrated in a metal center and now
这道题未画线的部分lined with lead ……应该也是指前面的主语，也就是the discus，那么把它和lined with lead 联系起来，不难发现应该少了一个is这个动词。和选项D是同样的错误。不知道这么理解OG的解释对不对。欢迎找错哦。

-- by 会员 liulu007 (2011/12/16 21:11:29)

完全正确