BBC news 2011-01-16 加文本

1.As darkness fell and a curfew again came into force, reports came from the city centre that at least two people had been shot by troops in the main square.

that at least two people...是reports的同位语从句。

同位语从句与定语从句的不同之处：

1)从句的作用不同：同位语从句用来进一步说明前面名词的内容；定语从句用来修饰、限定前面的名词。
e.g. The news that our team has won the final match is encouraging. （从句说明“消息”的内容：我们队取得了决赛胜利。）
　　 The news that you told us is really encouraging.（从句对“消息”加以限定：是你告诉我们的，而非来自其他渠道。但消息是何内容却不得而知。）

2)that引导同位语从句时是一个纯连词，故不能用which替换；而that引导定于从句时是代词，常可以和另一关系代词which替换。
e.g. The fact that he is from Canada is new to me. （that不可换为which）

　　 The fact that surprised me is that he is not Chinese.（第一个that可换为which，第二个不行，因为它引导的是表语从句。）

3)引导同位语从句关连词，除that外，还可以根据句义使用任何其它疑问代词或副词；而定语从句不可用what, how, whether等引导。

2.Counting begins tonight, but final official results are not expected until early next month.

not until…
这个句型从形式上看是否定句，但并非否定意思。until也可单独使用，表示“直到……为止”。

The doctor didn’t start the operation until the room was bright enough.
医生直到房间里的灯足够亮了，才开始做手术。

Not until I began to work did I realize how much time I had wasted.
直到我开始工作，我才认识到了我已蹉跎了几多岁月。

3.The French health ministry is promising major changes to regulations for licensing drugs after a report said up to 2,000 people died from a diabetes drug that should have been withdrawn from the market 10 years earlier.

这句话的主干是：The French health ministry is promising major changes to regulations...after后是时间状语从句。that should have been withdrawn是定语从句，修饰diabetes drug。should have been是与过去事实相反的虚拟语气，原本应该退出，但实际上没有退出。