Progressive tenses are also called continuous tenses.
“Agree” is a verb, not an adjective. A common mistake is to say: “I am agree with you.” Just say “I agree with you.”
“Should” and “had better” are both modals used to give advice. “Had better” has a stronger meaning. “Must” is stronger than both of them, and is used for regulations, obligations, or requirements.
– James, you should park underground. (mild suggestion)
– James, you had better slow down. The road is very icy and we might have an accident! (strong suggestion)
– James, you must stop at the red light. (strong obligation or requirement)