Do you know the famous English saying “you can’t judge a book by its cover“?

Look at the conversation. Can you guess the meaning?

Nina: When I first saw Kelly, I didn’t have a good impression of her. But after talking to her, I realised she is a very nice person.

Anna: You can’t judge a book by its cover!

Does it mean…

a) the cover of a book is not important

b) you can never really know someone

c) you cannot know about a person or thing just by looking at the person or thing

d) you cannot know if someone is nice until you become friends with them

The answer is below　↓

Answer:

c) you cannot know about a person or thing just by looking at the person or thing