A Simple Sentence is one that has only one Finite Verb expressed or understood.
The earth moves round the sun.
This sentence has one subject – The Earth.
This sentence has only one verb – moves.
Since this sentence has only one verb, it is called Simple Sentence.
Other examples of simple sentence with only one verb are :
1. We go to Chennai.
2. He plays cricket.
3. They walk around this park.
4. It takes only Credit Cards.
5. She is my mother.
6. We get our books from our school-library.
7. There are only few students in the class-room.
8. My school admits only meritorious students.
9. There is my college.
10. You have invited my sister to your wedding function.
Each of the above sentences has only one verb. In addition, this type of sentence will have only one clause with one subject and one predicate.