Nice poster… but what’s the English mistake here?

Well, the correct answer is: Exhibition of LIVE spiders and scorpions.  The problem here is that the use of the adjective ‘live’ or ‘alive’ depends on whether it’s in the predicative or attributive position. What do you mean, I hear you cry? Well, here are two great links to more information about attributive and predicative adjectives, if you are a grammar geek like me and want to know the difference:

http://pediaa.com/difference-between-attributive-and-predicative-adjectives/

https://en.oxforddictionaries.com/…/attributive-and-predica…

Otherwise, just remember that there are some adjectives that have different forms depending on whether they are before a noun, or after a linking verb such as ‘be’ or ‘seems’.
So:
The spiders are alive.*
This is an exhibition of live spiders.**

*predicative adjective, not followed by a noun, subject compliment – ‘alive’ is giving information about the subject: spiders

**attributive adjective, followed by a noun –  ‘live’ is also giving information about the spiders, but here the subject is ‘exhibition’.

Her child is ill/sick so she has to look after him. (predicative adjective)
OR
She has to look after her sick child.  (attributive adjective)
NOT
She has to look after her ill child.

Can you think of any more examples?