Adverbs like 常常‘chángcháng’ (often), 频繁‘pínfán’ (frequently), and noun phrases like每季度 ‘měi jìdù’ (quarterly), 每年‘měi nián’ (every year), etc., are most commonly used as time frequency expressions.
[1] Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.
