▲在第一帖中，freeone老师的观点是：

since attained = which was attained since（后来实现的……）

▲在第二贴中，曹老师的观点是：

既然since作为介词不可后接过去分词，我们就没有必要再考虑介词或连词。我赞同蒋老师（freeone) 的分析，此时的since是个副词。

The objective, since attained, was to create a set of contractual rules that...

= The objective, which had since been attained, was to create a set of contractual rules that...

since指前面提及的一个时间或事件，主语the objective是在那个时间或事件之后才制定的。本句中主句谓语为一般过去时was, 也可以证明since并不是修饰主句谓语的。

我对比一下两位老师的观点，发现存在差异：

freeone老师认为，since attained = which was attained since（后来实现的……）

曹老师认为, since attained= which had since been attained

▲我倾向于freeone老师的观点，并提供一下理据：

  朗文

since : at a time after a particular time in the past 此後；後來

例如：

We were divorced two years ago and she has since remarried. 我們兩年前離了婚，之後她又再婚了。

柯林斯

ADV  副词(表示过去某事或某情况发生后不久又发生了另一件事)此后，后来 When you are talking about an event or situation in the past, you use since to indicate that another event happened at some point later in time.

【搭配模式】：ADV with v

About six thousand people were arrested, several hundred of whom have since been released...

约 6,000 人被捕，后来其中的几百人又被释放了。

因此，我认为：

The objective, since attained, was to create a set of contractual rules that...

= The objective, which was to be attained later, was to create a set of contractual rules that...

我参考一下相关文本，进一步升级我的观点：

The objective, since attained, was to create a set of contractual rules that...

= The objective, which has since been attained, was to create a set of contractual rules that...

下面是相关文本：

http://www.sohu.com/a/225657854_428362

ICC UNIFORM CUSTOMS AND PRACTICE FOR DOCUMENTARY CREDITS UCP 600

FOREWORD

This revision of the Uniform Customs and Practice for Documentary Credits (commonly called “UCP”) is the sixth revision of the rules since they were first promulgated(颁布） in 1933.

It is the fruit of more than three years of work by the International Chamber of Commerce’s (ICC) Commission on Banking Technique and Practice.

ICC, which was established in 1919, had as its primary objective facilitating（促进）the flow of international trade at a time when nationalism and protectionism（民族主义和保护主义） posed serious threats to （对...构成严重威胁）the world trading system.

It was in that spirit that the UCP were first introduced – to alleviate（缓和） the confusion caused by individual countries’ promoting their own national rules on letter of credit practice.

The objective, since attained, was to create a set of contractual rules that would establish uniformity in that practice, so that practitioners （从业者）would not have to cope with（应付） a plethora（过多） of often conflicting national regulations.

The universal acceptance of the UCP by practitioners in countries with widelydivergent（差异） economic and judicial systems is a testament to the rules’ success.

It is important to recall（记住） that the UCP represent the work of a private international organization, not a governmental body.

Since its inception（成立）, ICC has insisted on the central role （核心） of self-regulation（自律） in business practice.

These rules, formulated entirely by experts in the private sector, have validated that approach（验证了这种方法）. The UCP remain the most successful set of private rules for trade ever developed（贸易有史以来的发展）.

A range of individuals and groups contributed to the current revision, which is entitled UCP 600. These include the UCP Drafting Group, which sifted through more than 5000 individual comments before arriving at this consensus(共识) text;

the UCP Consulting Group,consisting of members from more than 25 countries, which served as the advisory body(咨询机构) reacting to and proposing changes to the various drafts;

the more than 400 members of the ICC Commission on Banking Technique and Practice who made ertinent(相关) suggestions for changes in the text;

and ICC national committees worldwide which took an active role in consolidating comments from their members. ICC also expresses its gratitude to practitioners in the transport and Insurance industries, whose perceptive suggestions honed the final draft.

Guy Sebban

Secretary General

International Chamber of Commerce

既然since作为介词不可后接过去分词，我们就没有必要再考虑介词或连词。我赞同蒋老师（freeone) 的分析，此时的since是个副词。

The objective, since attained, was to create a set of contractual rules that...

= The objective, which had since been attained, was to create a set of contractual rules that...

since指前面提及的一个时间或事件，主语the objective是在那个时间或事件之后才制定的。本句中主句谓语为一般过去时was, 也可以证明since并不是修饰主句谓语的。