1. How poor the school is? <-- Incorrect 2. How poor is the school? <--Correct 3. You can imagine how delightful I felt? <--Incorrect 4. You can imagine how delightful was I? <--Incorrect For numbers 3 and 4: If you are asking a question, the phrase would be: Can you imagine how delighted I was? If you are stating a fact, the phrase would be: You can imagine how delighted I was! Remember that you are delighted. Delighted is an emotion. Delightful is an adjective that describes things or people. If you find something delightful, it makes you feel delighted.