BBC news 2010-07-26 加文本

1.The blast was in an area that was occupied by anti-government "red-shirt" protesters for weeks until the army was sent in on May 19th.

结构分析：这句话的主干是：The blast was in an area。后面是that引导的定语从句。until引导时间状语从句。

2.It’s not clear if the bombing was connected to a by-election in Bangkok, in which a leader of the protest was standing despite being in jail.

这里的it是形式主语，真正的主语是if the bombing was connected to...in which是定语从句，修饰的是Bangkok。

介词” + “关系代词”引导的定语从句中，介词的选取应根据如下几点：
　　
　　1)根据介词和定语从句中谓语动词的习惯搭配。如：
　　
　　Who is the man with whom you just shook hands？ 刚才和你握手的人是谁？
　　
　　The two things about which Marx was not sure were the grammar and some of the idioms。 马克思不大有把握的两个方面是语法和某些习惯用语。

2)根据定语从句意思的需要，此时不但要注意其前的搭配也要注意其后的搭配。如：
　　
　　He had a bad cold， because of which he didn””t attend the meeting。 他患了重感冒，因此未能参加会议。
　　
　　The speed at which the car runs depends on the road condition。 这辆车的速度要根据路面状况而定。

3)根据意思也可用复杂介词，如 by means of ，as a result of， in front of， in the back of ，all of ， most of 等，如：
　　
　　The instrument by means of which the temperature is measured is called thermometer。 用来测量温度的仪器叫温度计。
　　
　　There are forty students in the classroom， all of whom are working hard at a problem in mathematics。 教室里有四十个学生，他们都在努力计算一道数学难题。

3.President Sebastian Pinera of Chile has rejected a proposal by the Roman Catholic Church that he pardon members of the armed force convicted of human rights abuses during military rule in the 1970s and 80s.

结构分析：这句话的主干是：President Sebastian Pinera of Chile has rejected a proposal。that he pardon members of....是proposal的同位语。