解答如下

连接副词where引导地点状语从句，在....的地方/情况下

where引导地点状语从句时, where是从属连词, where引导的从句修饰主句的谓语动词。在....的地方/情况下.

Hero worship is strongest where there is least regard for human freedom. 

在人的自由最不受到尊重的地方,英雄崇拜最盛行。

Wuhan lies where the Changjiang River and the Han Jiang River meet.

武汉位于长江和汉江交汇处。

Make a mark where you have any doubts or questions.

在你有疑问的地方做上一个记号。

I found my books where I had left them.

我在我遗忘的地方找到我的书。

关于连词where引导定语从句和状语从区区别

定语从句还是状语从句的区别主要可以从以下三点来看：

(1)where引导定语从句时, where是关系副词, 在从句中作地点状语, 其前面有表示地点的先行词, where引导的从句修饰先行词。

The bookshop where I bought this book is not far from here.

This is the house where I lived two years ago.

We will start at the point where we left off.

(2)where引导状语从句时, where是从属连词, where引导的从句修饰主句的谓语动词, where前面没有表示地点的先行词。

Wuhan lies where the Changjiang River and the Han Jiang River meet.

Make a mark where you have any doubts or questions.

I found my books where I had left them.

有时, where引导的地点状语从句兼有抽象条件含义, 可放在主句的前面, 而where引导的定语从句则不能。

Where there is a will, there is a way. 〔谚语〕有志者事竟成。

Where there is water, there is life. 有水的地方就有生命。

(3)在有些情况下, where引导的定语从句可转换为where引导的地点状语从句。

A tall building was put up at the place where there used to be a desert. 

（＝A tall building was put up where there used to be a desert. ）

在以前曾是沙漠的地方盖起了一幢高楼。

Bam boo grows best in places where it is warm and where it rains often. 

（＝Bamboo grows best where it is warm and where it rains often. ）

温暖而多雨的地方最适合于竹子生长。

补充：only虽然处于中位状语的位置，但其实它修饰的是where从句。句子可以改写为：

Businesses may hire foreign workers only where an American cannot be found.

Businesses may only hire foreign workers where an American cannot be found. 在找不到美国人的情况下企业才可以雇用外国工人。

请问这个句子中的 where 用得对吗？【答】对！

如果句子是对的，那这个翻译对吗？【答】对！这个where是连词。以下内容摘自《牛津高阶英汉双解词典》第8版的where词条：conj.(in)the place or situation in which (在)......的地方；（在） ...... 情况下：...