Even though the bottle is tightly stoppered, the scents will be evaporated after a long time. 只有巧妙利用香水，才能让你在不同场合，扮演各种不同的角色，发挥你的魅力。
Of course, many problems recur at various periods. 当然，有许多问题会在不同的时期反复提出。
She has devoted herself to an extensive variety of public subjects, at various time, and is at present devoted to the subject of Africa. 她在不同的时期，热心研究过种种不同的公共问题，目前，正致力于非洲问题。
