感觉这篇语法填空难度颇大，第一遍看得头晕脑胀——话题新，生词多，句子长，考查“偏”。当然，从做题角度出发，并不需要透彻地理解文章意思。连蒙带猜，再加上点运气，也许能获得较高的正确率。不过还是有一个地方困扰我很久，那就是答案中that定从的先行词到底是谁？虽然随便猜一个并不影响做答案。

that所在句很长，而原句更长。

高考句：

The Glasshouse stands as a great achievement in contemporary design, to house the plants of the southwestern part of China at the end of a path retracing the steps along the Silk Route that brought the plants from their native habitat in Asia to come to define much of the richness of gardening in England.

原句：

It stands as a crowning achievement in contemporary design, to house the flora of sub-tropical south-west China at the end of a path retracing the steps along the Silk Route, from temperate Europe and across mountains, arid lands and high pastures that brought the plants from their native habitat in Asia to come to define much of the richness and glory of gardening in England.

拿原句来看，that前的名词短语有high pastures、mountains, arid lands and high pastures、the Silk Route、the steps、a path。我被每种可能都折磨了一遍，最后想到，根据语义，能够和brought the plants from ... to形成较合理搭配的名词短语有a path、the steps和the Silk Route。

考虑到the Silk Route是专有名词，使用that不太合适，答案就在a path和the steps中选。其中，这里的path与上文的The garden also contains a winding path that guides visitors through the twelve regions of the Silk Road. The path offers over 300 plant species for visitors to see, too.这两处的path所指相同，都是指现实世界丝路花园里的实体小路，并不能说这条丝路将植物带来，而带有历史意味的steps along the Silk Route能够做到这一点，并且根据retrace我们可知，后面的steps是来时的路（步子），这才是把植物带过来的路，path所做的只是retrace。整个句子包含的一层意思是a path that retraces（现在时） the steps that brought（过去时） the plants to ...此外，定语从句能够与定冠词限定的steps 构成更好的限定关系。试比较：

a path that brought the plants from ... to

the steps that brought the plants from ... to

基于上述两点，倾向于将(the) steps along the Silk Route视为that定从的先行词。

最后来几个结构类似的句子：

Let me briefly retrace the steps that have brought us together here today.

A tropical thunderstorm started to break as she retraced the steps that brought her from the US to Laos ...

This Route retraces the steps that the North American romantic writer and diplomat Washington Irving followed in 1829, ...

This 8.5 mile stretch of paved walking and biking path retraces the steps that Lewis and Clark took when they arrived here in November of 1805.