I believe 周、星期和礼拜 can be used pretty interchangably. All three mean week. I listed them ordered by degree of formality, and 周 doesn't take a measure word when you count them (it is a measure word itself for counting cycles, and the 7 day period is implicit). In my experience, days of the week are more often composed from 周 or 星期 (e.g. 周一, 星期一). People from Taiwan seem more prone to using 礼拜 than people from the mainland.
mark
August 05, 2012, 03:39 AMI believe 周、星期和礼拜 can be used pretty interchangably. All three mean week. I listed them ordered by degree of formality, and 周 doesn't take a measure word when you count them (it is a measure word itself for counting cycles, and the 7 day period is implicit). In my experience, days of the week are more often composed from 周 or 星期 (e.g. 周一, 星期一). People from Taiwan seem more prone to using 礼拜 than people from the mainland.