For number three, verbs of state are usually not used in the continuous aspect. For example: Believe, see, look, feel, hear, have (i.e. possess), think.
Dynamic verbs can be used in the continuous aspect: Watch, look at, look for, feel, listen, have (fun, a party, etc.), think.
State: He feels well / He looks well. He thinks Chinese is difficult.
Action: He is feeling the texture of the cloth. He is looking for something. He is thinking about his mother.