1. Simple Sentence:
- The cat sat on the mat.
- She sings beautifully.
2. Compound Sentence:
- The dog barked, and the cat meowed.
- I went to the store, but it was closed.
3. Complex Sentence:
- I saw the man who lives next door.
- I will go to the party if I am invited.
4. Compound-Complex Sentence:
- The woman who lives next door is a doctor, and she is very intelligent.
- I will go to the party if I am invited, but I will leave early if I am tired.