The term SHOULD is used to express an obligation or recommendation. It is often used in conjunction with other words such as HAVE, INCASE, AUGHT, MUST, OUGHT, GOTTA, and OUGHTTO. HAVE is a verb meaning to possess or own something. INCASE is a preposition meaning in the event that. AUGHT is an archaic form of OUGHT, which is used to express obligation or duty. MUST is another verb used to express obligation or necessity. OUGHT is a modal verb used to express obligation or advisability. GOTTA is a slang version of HAVE to, which is used to express obligation or necessity. OUGHTTO is a combination of OUGHT and to, which is used to express obligation or advisability.