1.
They may endure as varieties for very long periods.
在极长时期内停留在变种阶段。
2.
Determination of time-temperature limits of plastics after exposure to prolonged action of heat
GB/T7142-1986塑料长期受热作用后的时间-温度极限的测定
3.
Nature grants long periods of time for the work of natural selection.
自然界允许极长的时期，给自然选择来进行它的工作。
4.
The magnesium anode rod should be inspected periodically and replaced when necessary to prolong tank life.
应该定期检查阳极棒,为了延长热水器的使用寿命,在必要时,更换阳极棒。
5.
the industrial revolution was a period of great turbulence.
工业革命时期是极为动荡的时期。
6.
lasting for an indefinitely long period of time.
无期限持续很长时期的。
7.
In this period the poor peasants, having long been trampled down and feeling that the victory of the revolution was uncertain, frequently yielded to the intermediate class and dared not take vigorous action.
此时期内，贫农因长期地被摧残及感觉革命胜利无保障，往往接受中间阶级的意见，不敢积极行动。
8.
It is natural enough after long years of childhood, when you were completely under your parents' control.
[参考译文]于童年时代长期完全受父母的管束，形成这种消极看事物的方法是很自然的。
9.
It is also possible that these animals migrated into these areas during the warm summer months and retreated to lower latitudes ahead of the cold and long polar nights.
也可能是它们每年在温暖的时期迁徙到这些地区，而又赶在极区寒冷的长夜到来之前离去。
10.
On the Negative Influence of the Long-term Active Financial Policy;
论长期实行积极财政政策的负面影响
11.
The period of greatest popularity, success, or power;prime.
极盛时期繁荣、成功或力量的最高潮；全盛时期
12.
They have fought militantly through the two periods of underground work and of open activity.
从秘密时期到公开时期，贫农都在那里积极奋斗。
13.
Youth is the time of physical growth.
青年时期是长身体的时期。
14.
Remark: The event can be short or long.
注:事件能够是短时期或长时期的。
15.
The hot season is very long.
高温时期持续很长。
16.
Seven years was a long time!
七年也是一个长时期呢！
17.
The limit of this ratio as the length of the arc approaches zero.
曲率极限当弧长趋向于零时该曲率的极限
18.
How do you feel after doing it for so long?
你打了这么长时间的太极拳，感觉如何？