as of 是美国英语特有的表达方式,可以表示两个截然相反的时间点概念,具体分为以下几种用法:
as of 表示“截至…之时为止”。这个表达通常用于描述某一时刻或某一日期为止的情况。谓语动词可以用一般现在时、现在完成时或过去完成时。
例如:
As of this writing, the report has not been finalized.(截至本文执笔时,报告尚未定稿。)
As of March 2000, Japan's Internet users exceeded 21 million, ranking second only to the US's 124 million.(截至2000年3月,日本的互联网用户已经超过了2100万,仅次于美国的1.24亿。)
This version reflects the law as of November 27, 2002.(这个版本反映了截至2002年11月27日的法律。)
As of June 2, 2006, USCIS had approved 1,901 petitions under the 20,000 H-1B numbers reserved for US master's degree holders.(截至2006年6月2日,美国公民及移民局已经批准了1901份H-1B签证申请。)
注:as of 强调某一时间点或某一日期为止的状态,区别于until,后者通常指的是“延续到某一时间点就发生了变化”。例如,As of last year, they still had some concerns to resolve.(截至去年,他们仍然有一些问题需要解决。)
当谓语动词是被否定时,as of 表示某个否定状态直到某个时间点仍然保持,今后如何不交代。
例如:
As of Saturday, the governor still had not declared a state of emergency.(截至星期六,州长仍未宣布紧急状态。)
As of now, we haven't received any further updates.(截至目前,我们没有收到任何进一步的更新。)
与until不同,as of 不表示从否定状态到肯定状态的转变。
当as of 后面加上yet,成为as of yet,表示“截至目前为止”。如果谓语动词被否定,as of yet 表示否定状态直到现在仍然保持。
例如:
As of yet, no timetable has been set for construction.(截至目前,尚未确定建设的时间表。)
As of yet, no one has responded to the invitation.(截至目前,尚无任何人回应邀请。)
as of 还可以表示“自某时间点起开始实施某项措施”。这种用法常用于宣布某项新政策或改变。
例如:
As of January 31st, 2006, Internet Explorer for the Mac is no longer available for download from Microsoft.(自2006年1月31日起,Mac版Internet Explorer将无法再从微软网站下载。)
The border, effectively closed since 1981, will be opened as of January 1.(自1月1日起,边境将重新开放。)
as of 还可以表示在某个时间点即将发生的事情,通常用于表达计划或预测。
例如:
As of Monday, I will talk to him about it.(从星期一开始,我将与他讨论此事。)
As of next week, I will be working from home.(从下周起,我将在家工作。)
如果某个行动是立即要发生的,通常不适合使用as of。例如,不能说Right now (*As of now) I will cross the street.(我现在马上就过街去)。
同样,as of 也不适用于即刻生效的情况,通常预示着某个计划或事件将在不久的未来发生。