Here are two sentences:
Egypt began as a group of villages. It became one of the first great civilizations.
There are two predicates.
The predicates are underlined.
Both of the predicates tell about Egypt.
We can join the two predicates with "and" like this:
Egypt began as a group of villages and became one of the first great civilizations.
Here is another example. See if you can find the predicates.
The pharaoh was the most important person. He made all the big decisions.
Here is how we use "and" to join the predicates:
The pharaoh was the most important person and made all the big decisions.