expansion of a book cannot be judged by its cover
Answers
The English idiom "don't judge a book by its cover" is a metaphorical phrase which means "you shouldn't prejudge the worth or value of something by its outward appearance alone". For example "That man may look very small and insignificant, but don't judge a book by its cover – he's a very powerful man in his circle".
Don’t judge a book by its cover:
This proverb "Don’t judge a book by its cover" refers, we must not decide about something just looking a small part about it. Similarly, this phrase define, we must not judge anything about the cover, We must think before speaking, we must have a good knowledge on the topic we speak before we tell anything about it. This is very useful and most famous proverb.
Example: If you find a boy/girl always playing and he/she doesn't learn if you think it's wrong because he/she may learn well, It is wrong to judge about someone without knowing about their background. Also, you must not judge wrongly without knowing about someone's tallest.
Conclusion: Never judge anything wrongly, without knowing about it clearly.