同学你好，该知识点来自沪江网校《新概念英语第四册【天猫专享】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
to see a case in which the voice plays a strictly utilitarian role
这里是to see引导的不定式短语作目的状语。

case在这里是“例子，案例，情况”的意思。which引导定语从句，修饰case

which指代a case，in which相当于in a case

in which the voice plays a strictly utilitarian role 相当于
the voice plays a strictly utilitarian role in a case 在这个情况中，声音有绝对的实用价值。

I only know of one case in which this has happened.
我只知道在一种情况下发生过这种事情。

But this is the rare case in which being honest helps both you and your competition.
但这次是罕见情况，诚实能帮助你和你的竞争对手。




这句话涉及的语法：

in which属于“介词+关系代词”引导定语从句
当关系代词在定语从句中作介词宾语时，我们通常用“介词＋关系代词”引导定语从句。如果指“人”，用“介词＋whom”；如果指“物”，用“介词＋which”。

This is the house in which we lived last year. 这是我们去年居住的房子。
这个句子相当于This is the house which we lived in last year.
which指代的是house，实际上which we lived in中which是in的宾语，这种情况下可以把in提前到which前，变成in which we lived

Copper is one of the metals with which we are most familiar.铜是我们最熟悉的金属之一。（形容词familiar与with连用）

Please tell me from whom you borrowed the English novel. 请告诉我你从谁那借的这本英文小说。（动词borrowed和from连用）



介词+关系代词引导定语从句时，介词往往受上下文的约束，究竟使用哪个介词时得从下面几方面来进行考虑。

(1) 从先行词跟介词的搭配习惯出发。如：

In front of my house, there is a tree, in which some birds are singing. 我的房子前有一棵树，鸟儿正在树上唱歌。(在树上一般用介词in)

(2) 从定语从句中的动词、形容词对介词的习惯要求出发。如：

The computer for which I paid 5,000 yuan is made in Shenzhen. 我花了五千元所买的这台电脑使深圳造的。( pay 与for搭配)

(3) 从先行词、定语从句中的动词或形容词两方面同时考虑出发。如：

Do you know the girl with whom the man talked just now? 你认识跟那个男谈话的女孩吗？(talk 究竟接with还是接about, 这该由动词及现行词一起决定，因为这里是跟人说话，不是谈论物，所以用talk with)

(4) 复合介词+关系代词。如：

Go down this road, at the end of which you can see a high building and it is our office building. 沿着条路走，在路的尽头你会看到一座高大的建筑，那就是我们的办公大楼。

(5) 名词/代词+介词+关系代词。如：

I saw three camp beds, two of which were occupied. 我看见了3张折叠床，其中两张已有人占了。

同学也可以看看这里，对介词+关系代词的详细解释
https://www.hjenglish.com/new/p1189200/

祝同学学习进步~