1. Can be achieved by a brief period lying, or even sitting down.
    只要稍微躺一躺，甚至坐一坐就能达到。

2. But a closer study of the evidence, supported by a deeper sense of the period, and particularly by a new consciousness of the philosophical undercurrents in the scientific revolution, has profoundly modified this view of Galileo.
    但是，对那个时代的深化了解，尤其是以科学家革命中哲学潜流的新意识为依据，进一步仔细研究，就会极大地改变对伽利略的看法。

3. But it was still too short a period for men to base a calendar on.
    但时间依然太短，人们无法以此为据制定历法。

4. When research into cloning is resumed, human cloning should remain a research activity for an extended period.
    当克隆研究重新开始时，克隆人类应该仍然是一项历时长久的研究活动。

5. The Qin dynasty existed for a very short period.
    秦朝存在的时间很短。

6. The period following the Civil War said "Get set!";
    内战后的那段时期说"预备！

7. He could not have had a better mentor during this very trying period.
    在这艰难的时刻他不可能找到比这位更好的老师了。

8. He was born in that turbulent period of history.
    他出生在那个动荡的历史时期。

9. And another group were disturbed for an equal period of time but when they were not exhibiting eye-movements,
    另一组人也是连续几夜被叫醒，但是在眼球队没活动时被叫醒的。

10. And a period (which is the time it takes a wave crest to travel one wave length).
    和周期（海峰走过一个波长所需的时间）。