This study explored teacher questioning as a formative assessment strategy by examining the practices of teachers of English as a Foreign Language in Chinese tertiary institutions. It investigated how teachers deployed questions to stimulate student thinking, uncover students' current level of learning, and allow responses to inform pedagogic decisions. The research methods were classroom observations and interviews. This paper highlights the practice of one experienced teacher who conducted quality questioning to gauge and facilitate learning. The paper provides practical insights into how questioning can be developed as a formative assessment method and recommends equipping teachers with further knowledge and skills to carry out effective questioning.