Schachfreizeit
Does which always introduces a non-essential modifier? I feel like sometimes there is something after which that is important for understanding the sentence...
It can be important to understanding the sentence, but structurally it's still considered 'non-essential.'
A good example to understand why:
"I ate lunch at the best restaurant in the city, which serves hamburgers."
"I ate lunch at the best restaurant in the city that serves hamburgers."
In the first, I ate lunch at the best restaurant of all restaurants in the city. That restaurant does serve hamburgers.
In the second, I looked at the category of restaurants, the ones that serve hamburgers, and ate at the best restaurant in that category. It might not be the best restaurant *overall* though.
Don't think of 'essential' and 'non-essential' as terms about 'understanding.'
For instance, in the sentence, "In a sense, he did marry her for her money, which she earned by developing a medicine that saved the lives of thousands of people."
The 'which' modifier drastically changes our understanding of the sentence. At first, we might think 'marrying for money' is kind of a bummer reason to marry somebody... But then the detail of how that money was made changes our understanding of the scenario drastically. However, that is still considered a 'non-essential' modifier. (Now, that sentence is a little more 'artistic' and and ironic than the GMAT would be, but it gives an example of how 'which' can be used for important information that is still, technically, 'non-essential').
But it is a general rule that if sth is introduced with which, the following is not necessary right? So if the information is necessary, it should never start with which?