1. The change prevented the decline in efficiency that so commonly spoiled the fortunes of family firms in the second generation after the energetic founders.

(1) 句子基本结构为 The change (主语) prevented (谓语) the decline (宾语)。

(2) in efficiency 为介词短语，作定语，修饰名词 decline。

(3) that so commonly spoiled the fortunes of family firms in the second generation after the energetic founders 为 that 引导的定语从句。其中 that 为关系代词，除引导是定语从句外，还在定语从句中用作主语。定语从句所修饰的先行词是 decline（注意不是 efficiency）。

句子大意：这种变化防止了效率的降低，而这种效率的降低在精力充沛的创业者之后的第二代人经营公司的时候，经常会毁掉这些家族公司的财富。

2. Towns like Bournemouth and Eastbourne sprang up to house large “comfortable” classes who had retired on their incomes, and who had no relation to the rest of the community except that of drawing dividends and occasionally attending a shareholders' meeting to dictate their orders to the management. 

(1) 句子的基本结构是Towns... sprang up to house... classes。

(2) classes 后跟有两个who引导并列的两个定语从句（修饰先行词 classes）。

(3) 句中的 except为介词，其后的 that 为代词，用于替代 relation，except that of… 相当于 except the relation of…。

句子大意：诸如伯恩茅斯和伊斯特本这类城镇的出现，给那些数量庞大的“舒适”阶级提供了居住之处。这些人靠自己的丰厚收入而无需工作，除了领取股息和偶尔参加股东会议向管理层发号施令外，他们与社会的其他阶层没什么联系。

3. The paid manager acting for the company was in more direct relation with the men and their demands, but even he had seldom that familiar personal knowledge of the workmen which the employer had often had under the more patriarchal system of the old family business now passing away. 

(1) 句子基本结构为 The paid manager…was in…, but even he had seldom that familiar personal knowledge…（为并列连词but连接的并列句）。

(2) 在第一个并列分句中，The paid manager 为主语，acting for the company 为现在分词作定语，修饰manageer；was in more direct relation with the men and their demands 为系表结构。

(3) 在第二个并列分句中，主语是 he，谓语是 had，宾语是 that familiar personal knowledge of the workmen。其后的 which the employer had often had under the more patriarchal system of the old family business now passing away 为定语从句，修饰先行词 knowledge。句中的 that 只是一个代词，并不是引导从句的“引导词”。

句子大意：花钱请来代表公司的经理与工人们的关系更直接，对他们的需求更清楚，但是就连他也很少有雇主曾有的那种对工人们的切身了解，而在正在消失的古老家族企业的那种更加家长式的体制下，雇主通常都有这种切身了解。