1. Employment became widespread when the enclosures of the 17th and 18th centuries made many people dependent on paid work by depriving them of the use of the land and thus of the means to provide a living for themselves. 【结构分析】句子的主干为“Employment became widespread”；“when the enclosures of the 17th and 18th centuries made many people dependent on paid work”为when引导的时间状语；“by depriving them of the use of the land and thus of the means to provide a living for themselves”为方式状语。
2. A new Research Council report on school bus safety suggests that there are alternate safety devices and procedures that may be more effective and less expensive. 【结构分析】句子的主干为“A new Research Council report on school bus safety suggests that there are alternate safety devices and procedures”，其中“that there are alternate safety devices and procedures”为that引导的从句充当“suggests”的宾语；“that may be more effective and less expensive”为that引导的从句充当“alternate safety devices and procedures”的后置定语。
