BBC news 2010-05-19 加文本

1.I think this announcement is as convincing an answer to the efforts undertaken in Tehran over the last few days as any we could provide.

as  as

带as(so)… as的结构

  1)在表示“和…一样…”时，可用“as... as”结构(前面的as后要用原形)：
  He is as busy as before. 他还是和以前一样忙。
  I’ll give you as much help as I can. 我将尽量帮助你。
  The airport was as crowded as ever. 机场还是像平常那样拥挤。
  You’re as good a singer as Johny Buck. 你的歌唱得像约尼·伯克一样好。
  Modern computers can be as small as a book. 现在的电脑可以像一本书那样大。

  2)在表示“不像…那样…”时可用“not as(so)... as”这种结构：
  It isn’t so cold as yesterday. 今天不像昨天那样冷。
  He is not so handsome as his brother. 他不像他哥哥那样英俊。
  I’m not so experienced as you think. 我没有你想的那样有经验。
  The situation is not so bad as had been painted. 形势没有描绘的那样糟糕。
  Jack is not as(so) old as he looks. 杰克不像他看起来那样老。

  3)这种结构中也可包含一个状语或有almost, just, nearly, quite这类副词形容：
  The whale was twice as long as her boat. 那头鲸有她的那艘船的两倍长。
  Their house is about three times as big as ours. 他们的房子约为我们房子三倍大。
  My command of English is not half so good as yours. 我的英语掌握得还不及你的一半好。
  He was almost as diligent as his sister. 他几乎和她姐姐一样勤奋。
  She is nearly as tall as her mother. 她几乎和她妈妈一样高。

  4)as... as还可用在许多固定说法中：
  as brave as a lion
  as busy as a bee
  as vain as a peacock
  soft as velvet
  as bright as day
  as fat as a pig
  as gentle as a lamb
  easy as ABC

2.The BBC UN correspondent says the announcement is significant a day after Turkey, Brazil and Iran reached a nuclear fuel swap agreement, which they said removed the need for further sanctions against Tehran.

这句话的主干是：The BBC UN correspondent says the announcement is significant。a day after...是时间状语。which they said...是定语从句，修饰agreement。