Practises: yes/no questions
Teacher prepares stickers with a profession on each one. The stickers are affixed to students' foreheads. Students try to discover their own profession by asking yes/no questions (do I work at night? am I rich? do I wear a uniform?) in turn. Works best in smallish groups.
Students should be encouraged to think of the usual question words (where do I work? when do I work? why? who? how? how much? etc) and to formulate appropriate yes/no questions to obtain the required information.
Some suggested "professions":