1.B
他们的父母,先行词children在定语从句中用作children's 定语,即their children 所以关联词要用whose
2.A
先行词 a job,在定语从句中的作用,放进去看一下,you are doing something serious but interesting (in this job),在此工作中你正在从事一些重要但很有趣的事,在这件工作中,作地点状语,所以关联词用where
3.C
先行词是 house,放进定语从句中,是the roof of the house,所以关联词用of which,用相象的whose不能用,如果是its 用whose
4.A
这还一个定语从句,先行词是season,在定语从句中作主语,the season follows spring,跟随着春天的季节,所以关联词用which/that,不能用who,who指代人,如果指代物要用which或that,没有which则选that
5.简单句改含有定语从句的复合句.
（1） A student's article was published last month ,I know that student.
-> I know that student,whose article was published last month.
（2） I was reminded of my dog Xiaobai,The dog’s bravery had moved us greatly.
-> I was reminded of my dog Xiaobai,whose bravery had moved us greatly.