Should we understand every word in a article?

[Unregistered]

Dear Teacher :
Good night !
I have been puzzled for a long time that is it necessary for us to look every new word in a article up in a dictionary in order to enlarge our vocabulary ?

[Soup]

Dear Teacher :
Good night !
I have been puzzled for a long time that is it necessary for us to look every new word in a article up in a dictionary in order to enlarge our vocabulary ?

Research tells us that we can acquire about 9 new words a day. And by 'acquire' I mean be able to use without thinking about the grammar. If you try to learn more than 9 words a day, you'll probably forget most the next day. So, focus on what you need to know; look to the context to help you with the meaning of words that you don't know.


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Correction
Good evening!, not good night.