1.Walking for 40 minutes a few times a week is enough to preserve memory and keep ageing brains on top form, research shows.
研究显示，1周几次40分钟的散步，足以保存记忆且让老化的大脑保持巅峰。
2.To preserve memory and for optimal operation of the switch, learned entries may be discarded from the MAC address table.
为了保留记忆体并且考虑到交换器的理想运作，已经学到的记录有可能从MAC位址表中移除。
3.Men should be pay more attention to food and practices that can help enhance and preserve memory over the long term.
那就是——人们应该多注意自己的饮食和锻炼，这对他们记忆力的提高和记忆量的储存都有长期的帮助。
4.But in the case of larger trees, we might prefer to traverse iteratively, in order to preserve memory.
但对于较大的树来说，我们更希望以迭代的方式遍历，从而节约内存。