“首要的”的英语？

首要的难题是，过时也好，不过时也罢，它很不错。The first difficulty is that, old-fashioned or not, it is very good.首要的治疗方法就是通过定期滋润来帮助受到影响的皮肤。The first line of treatment is to help the affected skin by moisturising it regularly.他对年轻画家言简意赅的建议是，“首...