But if improving their hunting luck was the chief motivation for the paintings, it is difficult to explain why only a few show signs of having been speared.
但是，如果增强他们的狩猎运气是这些画的主要动机，那么就很难解释为什么只有少量画作有被长矛刺过的迹象。
I want you guys to think about why it was difficult to do it another way, which is more pedestrian.
我希望你们能思考一下为什么用另一种更普遍的方法来做比较困难。
The English language is made up of the grammar and vocabulary which people from many different countries brought to Britain and that is why English has so many difficult rules that confuse people.
来自不同国家的人们把词汇和语法带入英国，形成了英语，这就是为什么英语有那么多让人困惑的规则的原因。
Why is it so difficult to take that first step?
为什么迈出第一步如此困难？
So again I ask myself, why is it so difficult to install one of these seats?
所以我再一次问自己，为什么安装一个座椅如此困难？
In the current Labour market, it isn't too difficult to understand why a worker would do this.
在当今的劳动力市场上，并不难理解为什么很多人选择零报酬工作的做法。
In the bunker, where ice crystals have formed on the ceiling in perfect geometric squares, it quickly becomes apparent why it's so difficult to build on permafrost.
在地坑里，冰晶在天花上结成了完美的几何块状。我很快就明白了为什么在永久冻土带上建筑房屋很困难。
This may explain why the European Central Bank has found it so difficult to get euro-zone inflation back below its target of 2%.
欧洲央行对此深有体会，她已经察觉到要使通货膨胀率重回2%——欧元区的通货膨胀率目标——以下是多么困难。
It's a difficult thing to do these things and that's why we need invention.
做这些事很难，这正是我们需要发明的原因。
Subsequent chapters explain why so many individuals find it so difficult to forgive, and why holding onto grievances is really a decision to suffer.
随后的一张解释了为什么有很多个体发现要你宽恕一个人真的很难，为什么会有没办法原谅他人的理由，为什么抱怨回事痛苦的来源。
Why is it difficult for a self-teaching language learner to keep his zeal through to the end?
外语自学者为何往往难以把学习“冲劲”保持到底？
Danah then moved on the talk about the reasons why social will find translation to mobile difficult.
Danah随后探讨了为什么将“社会”的移动应用会存在困难。
Decisions like these are very personal and difficult to make, which is why they must be respected and not commented on.
像这些完全是个人决定并且是很难作出的，这也是为什么我们必须尊重并不要妄加评论。
But working out how to do that is difficult, which is why deforestation got left out of Kyoto.
但是，如何处理这件事是非常困难的，这就是为什么砍伐树木没有进入《京都议定书》。
The seven "Yes's" speak to why process improvements are difficult, and often require an outside catalyst -- one with built-in credibility and process experience for bootstrapping positive change.
七个“是的”证明了为什么过程改进是困难的，并且经常需要外部催化剂 ——拥有内嵌的步步为营地积极变更的可靠性和过程经验。
What makes them laugh and cry, why are they temperamental, why are they so difficult to get along with, what do they really want?
是什么让他们欢笑和哭泣，为什么他们喜怒无常，为什么他们这么难相处，他们到底想要什么？
Typography is one of the most difficult trends to tackle which is why it will remain fresh in 2010.
设计字体是最难的设计风格之一，这就是为什么设计字体仍然是2010年的潮流趋势。
"It is difficult to know why this relationship occurs - for example, stress, genes - so more work needs to be conducted on the exact mechanism underlying it," he said.
“很难理解为什么会发生这样的联系——也许是压力，基因——所以目前尚有大量的工作需要处理以找出准确的深层机制，”他认为。
Can you briefly indicate why such a partnership has been so difficult to achieve in the past and why you think SOE can succeed in establishing such a partnership?
你能简要地指出为何这种合作在过去是如此难以实现，以及为什么你认为SOE可以成功地建立这种合作？
Given that, why is it difficult to attract interest in research in an area such as tuberculosis, even though it causes a large burden of disease across the world?
既然是这样，为何还很难使人们重视结核这类领域的研究工作，即使它在全世界造成了巨大的疾病负担？
However, it is difficult to understand why this information cannot be made available weeks or even months later.
然而，为什么这一信息不能在几周甚至几个月之后公布于众，这点很难令人理解。
It is not difficult to explain why such a "fireman" effect might exist. They are typically athletic men who face great physical risks, as a means of saving strangers' lives.
不难解释，消防员效应的存在，因为他们都是典型的体格健壮型男子，而且总是面对极大的身体风险，需要去拯救陌生人的生命。
At night, it's the extra-sensitive rods that take over — this is why it's difficult to detect color in low levels of light.
夜间，特别敏感的视杆细胞在眼睛视物占有主导地位—这就是为什么在昏暗的光线条件下我们很难看到事物的色彩。
It's not difficult to find out why: they have television; they have toys, computer games, personal VCRs, bikes and all the trappings of a well-off childhood; but they don't have books.
原因并不难找到：他们有电视，有玩具，有电脑游戏，有自己的录像机，有自行车，有钱人家孩子该有的他们都有，但是他们没有书。
The point is that the cacophony of analysis helps to explain why policymakers react in different ways to the same crisis and why it is so difficult for them to come up with co-ordinated action.
关键在于，分析上不和谐的声音，有助于解释政策制定者在同一场危机中，为何采取了不同的对策，以及他们达成协同行动为何如此困难。
The brain is resistant to arousal during deep sleep, which explains why it's difficult to wake a sleepwalker.
深度睡眠时大脑对外界的激励有抵抗力，这解释了为什么很难叫醒梦游者。
The brain is resistant to arousal during deep sleep, which explains why it's difficult to wake a sleepwalker.
深度睡眠时大脑对外界的激励有抵抗力，这解释了为什么很难叫醒梦游者。
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