once a year 前面要加for吗
2015-02-22 07:25:15
前面可以不用,例如:
1、The Tourist Board inspects all recommended hotels at least once a year.旅游局至少每年视察一次所有举荐的旅馆。
2、The snake sheds its skin once a year.蛇一年蜕一次皮。
3、Many people have made it a rule to detoxify once a year.许多人已经养成了每年进行一次身体排毒的习惯。
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