English is very rich in idiomatic language and these expressions are ones which students of English should know, and native English speakers use almost without thinking.
A row of trees in a London Suburb
1. He can't see the wood for the trees
This means he is so busy looking at the overall picture or subject that he doesn't notice the details
Pigeons eating bread on a London pavement
2. Birds of a feather flock together
This means that people with similar characteristics are drawn to each other - thus criminals or violent people tend to mix with others of a like nature and people of a certain political persuasion will tend to mix with others with the same leanings
3. The apple doesn't fall far from the tree
Meaning people tend to have similar family or cultural traits
4. A rose by any other name would smell as sweet
Means that what matters is not the mere name, but the essence of what something is.
This is a quote from Shakespeare's play, Romeo and Juliet:
"What's in a name? that which we call a rose
By any other name would smell as sweet"
Horse at the British Museum
5. Don't Look a Gift Horse in the Mouth
- Don't criticize things you get cheaply or for nothing
Did you learn anything new?
On this link you'll find 5 More Expressions About Nature