1. of course 是插入语 把他省略不看
则Dorothy was always speaking highly of her role in the play,which made the others unhappy .这样的话一看就知道是定语从句啦,which指代前面整个句子（Dorothy was always speaking highly of her role in the play）做从句which made the others unhappy 的主语.
（其实你只要看到有逗号就知道是非限制性定语从句,那肯定就要用WHICH啦）
what正如楼上所说跟定语从句没什么关系
2. 我们把at the new year party 省略不看,也就是the english play in which my students acted was a great success.
这句话还是定语从句的问题.主句是the english play was a great success,从句是in which my students acted ,which指代
the english play在定语从句中作in的宾语,即in the english play my students acted,也就是说my students acted in the english play.
3.如果你想选A,那你得把题目改了,在WITHOUT前加上句号.如果是两个句子就填it.
如果你想选B,那么我要告诉你,一般情况下THAT前面是不会出现介词的（如果你学的是牛津英语高一的话仔细看书,这个在某一个TIP里面提到过）,只有in that(因为),except that(除了……以外).
C是打死也不能选的,选他就不可饶恕啦
D呢,就是答案啦 WHICH 指代the map 做定语从句中WITHOUT的宾语.定语从句中,先行词前面有介词,用WHICH就好了.
~\(≥▽≤)/~啦啦啦结束 找本语法书 把定语从句好好看一看 规则是要先记住才会用嘛 （其实做多了以后,有了感觉,看一看就出来了）