Think of it like Lego blocks. You have a collection of different-shaped blocks (Greek roots), and you can combine them in various ways to create different structures (English words).
Here are some examples of common Greek roots:
* Auto-: self (automobile, automatic)
* Bio-: life (biology, biography)
* Geo-: earth (geology, geography)
* Graph-: write (graph, autograph)
* Hydr-: water (hydrate, hydroelectricity)
* Log-: word, speech (dialogue, logic)
* Micro-: small (microscope, microwave)
* Path-: feeling, suffering (empathy, sympathy)
* Phone-: sound (telephone, symphony)
* Photo-: light (photograph, photosynthesis)
* Tele-: far (television, telescope)
These are just a few examples. There are many more Greek roots in English, and they can be combined in different ways to create new words with unique meanings.