1. From the moment Mary Stuart arrived in Scotland at the age of 18 from the French court where she had been brought up, the relationship between the cousins was tainted with mutual suspicion.

結構剖析：這是一個簡單句，主語是the relationship between the cousins，謂語是was tranted with mutual suspicion，from the moment Mary Stuart arrived in Scotland at the age of 18 from the French court where she had been brought up是介詞短語做時間狀語。

在主語中between the cousins是介詞短語修飾名詞relationship；在謂語中was tranted是使用了被動語態；在介詞短語中含有兩個定語從句——Mary Stuart arrived in Scotland at the age of 18 from the French court where she had been brought up。定語從句中at the age of 18是做時間狀語，from the French是介詞短語做地點狀語，注意語序問題，表示時間的狀語位于表示地點的狀語。

這個定語從句由關系副詞when引導修飾先行詞moment。在這個定語從句中又含有一個由關系副詞引導的定語從句——she had been brought up，它修飾先行詞court。

2. At the first opportunity, Elizabeth behaved badly, almost irrationally, denying Mary safe conduct through England to her new realm and forcing her to sail the long way round to Scotland.

結構剖析：這個句子是含有2分詞短語的復合句。第一分詞短語是——denying Mary safe conduct through England to her new realm，第二個分詞短語是——forcing her to sail the long way round to Scotland，這2個分詞短語由并列連詞and連接。這2個分詞短語都做方式狀語或者也可以成為伴隨狀況狀語。

3. Though very much the injured party, Mary's response already betrayed the theatrical self-pity which so got up Elizabeth's nose.

結構剖析：這個句子是個含有定語從句的復合句。主句是——Though very much the injured party, Mary's response already betrayed the theatrical self-pity，從句是—— which so got up Elizabeth's nose。

在主句中，though very much injured party中的injured是過去分詞作定語修飾party，注意party在這里是“一方”的意思，副詞性短語very much是修飾injured這個形容詞。

定語從句是由which引導，因為先行詞是self-pity，它在定語從句中做主語，指代事情，那么可用的關系代詞which和that都可以，做主語關系代詞是不能省略的。