当定语从句的先行词是point，case，degree，position，activity，situation，stage，relationship等等抽象地点名词，表示某人或某物所处的情况或发展的阶段时，可以用关系副词where来引导。
定语从句的先行词是point（达到......程度）
We have reached a point where a change is needed.
定语从句的先行词是case（在......情形之下）
There are cases where the word‘mighty’is used as all adverb.
定语从句的先行词是position（在......情况下）
It is put me in a position where I can't afford to take the job.
定语从句的先行词是activity（在......活动范围中）
Those successful deaf dancers think that dancing is an activity where sight matters are more than hearing.
定语从句的先行词是situation（在......境地）
He got into a situation where it is hard to decide what is right and wrong.
定语从句的先行词是relationship（在......关系中）
Remember that the best relationship is onewhere your love for each other is great.
定语从句的先行词是stage（在......阶段）
Until today, we have reached a stage where we have almost no rights at all.
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where可以引导定语从句的。
比如：We visited the house where Einstein was born.
我们参观了爱因斯坦出生的房子。
勤学好问 天天进步！