if you want to see a doctor,you fix a date with him ahead of time.that ie a common__in the usa
问题描述：
if you want to see a doctor,you fix a date with him ahead of time.that ie a common__in the usa
a,method.b,rule.c,practice.d,habit
答
c
翻译：如果你要看病的话,要和大夫提前预定日期,这在美国是个惯例
common practice 固定搭配,惯例