The question "what type of sentence is this" is an example of an interrogative sentence. Interrogative sentences are sentences that ask a question and typically end with a question mark. They are often used in conversations, interviews, and surveys. Interrogative sentences can be classified into different types based on their function or structure. For example, polar questions require a yes or no answer, while wh- questions ask for specific information. By understanding the different types of interrogative sentences, you can improve your communication skills and effectively convey your message.