OG 184 E yet 的，解释

jade_lee

请问：OG 184 解释E 中yet 前需加“，”因为but ，yet 本身要求吗？

184. As measured by the Commerce Department, corporate profits peaked in the fourth quarter of 1988 and have slipped since then, as many companies have been unable to pass on higher costs.

(A) and have slipped since then, as many companies have been unable to pass on higher costs

(B) and have slipped since then, the reason being because many companies have been unable to pass on higher costs

(C) and slipped since then, many companies being unable to pass on higher costs

(D) but, many companies unable to pass on higher costs, they have slipped since then（A）

(E) yet are slipping since then, because many companies were unable to pass on higher costs

A, the best choice, observes an appropriate sequence of verb tenses a single act in the past (peaked) followed by an extended activity reaching to the present (have slipped). The as clause states clearly the cause of the slippage. B suffers from the redundant and unidiomatic expression the reason being because. In C, the use of the simple past slipped with since then is unidiomatic because since then denotes extended time. In D, the intrusion of the awkward many... costs causes the antecedent of they to become unclear. Furthermore, a comma should precede the but since it introduces a second independent clause. In E, yet also requires a comma before it, are slipping with since then is illogical, and were unable represents an ungrammatical tense shift.

buddyk

请参考：

http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=63237

请多使用搜索功能和 OG汇总链接：

http://forum.chasedream.com/dispbbs.asp?boardID=23&ID=27472&page=1

很多问题都已经被问过，并有NN精彩解答。要最快找到答案，请使用搜索和置顶贴。

谢谢你的理解和支持！

jade_lee

Buddyk,

Thank you for your prompt response, your instruction of using search engine of CD, and two links above.

Jade