? The gift was the Amber Room,
which was given this name because several tons of amber were used to make it.
非限制性定语从句 which指代the Amber Room; which作定语从
? The amber which was selected had a
beautiful yellow-brown colour like honey.
限制性定语从句 which指代amber; which 在从句中主语
It was also a treasure decorated with gold and jewels, which took the country’s best artists about ten years to make.
非限制性定语从句 which指代treasure; which 在从句中作主语
However, the next King of Prussia,
Frederick William I, to whom the amber room belonged, decided not to keep it.
非限制性定语从句 whom指代Frederick William I; whom 在从句中作to的宾语
Later, Catherine II had the Amber Room
moved to a palace outside St Petersburg where she spent her summers.
限从 where指代palace; where 在从句中作地点状语
In 1770 the room was complete the way
限从; way 还原：she wanted the way. way在定语从句中作宾语， 因此定语从句关系词用that/which引导或省略。
This was a time when the two countries were at war.
限从； when指代time; when 在从句中作时间状语。
that引导同位语从句。 that 不作成分
There is no doubt that the boxes were then put on a train for Konigsberg, which was at that time a German city on the Baltic Sea.
which指代Konigsberg; which 在从句中作主语