1. The dairymaids and men had come from their cottages as they saw the cows arriving from the fields．

【要点解析】划线部分saw the cows arriving from the fields中谓语动词saw后面的宾语的补足语是用现在分词arriving from the fields，对其宾语cows进行补充说明其行为。

2. Each girl sat on her three－legged stool as she milked,her right cheek resting on the cow's body,watching Tess arrive．

【要点解析】这是一个含有独立主格以及现在分词短语的复合句。独立主格和现在分词短语都在句子中做伴随状况状语。

独立主格是her right cheek resting on the cow's body，当挤奶员在坐在板凳上的同时，伴随着的行为时靠在奶牛的身上休息。

现在分词短语是watching Tess arrive。当挤奶员坐在板凳上的时候，正在看着苔丝归来，这2个动作时同时发生的。

3. One of them was a middle－aged man,the head－dairyman she was looking for．

【要点解析】这是含有定语从句的复合句。定语从句是she was looking for。它是限定性定语从句，修饰表示人的先行词head-dairyman。由于先行词在定语从句中做宾语，可用的关系代词that，who和whom都省略了。