Answer:1. We should wear a mask when going out. (recommendation)2. We ought to wear a mask when going out. (milder obligation)3. We must wear a mask when going out. (stronger obligation)4. We had better wear a mask when going out. (stronger advice)5. It's essential that we wear a mask when going out. (emphatic necessity)Additional options:1. We're supposed to wear a mask when going out. (formal expectation)2. We're required to wear a mask when going out. (official requirement)3. It's advisable to wear a mask when going out. (formal advice)