I have colleagues working in Scandinavia who are also responsible for the main cities in Europe.

【答】上述句子，若把现在分词短语 working in Scandinavia 改为who work in Scandinavia 或者who are working in Scandinavia，都不可以。

即,不可以说：

1. I have colleagues who work in Scandinavia who are also responsible for the main cities in Europe.

2. I have colleagues who are working in Scandinavia who are also responsible for the main cities in Europe.

原因如下：

1. 这属于“并列式定语从句”，两个从句之间必须加连词（and 或or，but等）。

2. 两个从句的关系代词（主语）重叠使用，除了啰嗦外，也不符合语言的表达规律。

3. 使用“并列式定语从句”时，两个从句应该体现出不同：不同的关系词；不同的时态；不同的结构；即便两个关系词相同，但两个从句的内容应相对或相反。例如：

The owner of the house whose wife is dead, whose son works in New York and who wants to go and live with him, is willing to sell the house at a low price. 这幢房子主人的妻子已过世，儿子在纽约工作，他想搬去和儿子一起生活，所以愿意以低价出售此房。

Mr. Smith, who has a good command of French and English but who doesn’t know Chinese, finds it difficult to study Chinese literature. 史密斯先生精通法语和英语，但对中文则一无所知，所以他发现研究中国文学很困难。

This is the house in which the famous man lived, which you visited 10 years ago and which becomes a museum now. 这就是那位名人居住过的房子，10年前你参观过，现在成了博物馆。

The old worker recalled that he would never forget the moment when he first met Premier Zhou and which he regarded as the happiest in all his life. 那位老工人回忆说他永远忘不了第一次与周总理相见的那一刻，那一刻被他视为人生中最幸福的一刻。

Paris is a good place, where art is so popular, and which many people appreciate. 巴黎是个好地方，那里艺术很流行，很多人喜欢那个地方。