句子中的where 是关系副词，引导定语从句，修饰名词cases，因此，in cases where the explanation is unknown可以译为在对一些的讲解还不为大家所知的状况下。用关系副词 where引导定语从句也是非常容易见到的，如：
1）Let's think of a situation where this idiom can be used （大家来想一个可以用这个习语的场所）
2）Is there a library around where we can borrow books？（附近有哪些图书馆可以借书吗？）
句子中that引导的是一个表语从句。表语从句和主句中的连系动词连用，结构为：主语＋连系动词＋表词从句，比如：
1）My idea is that we should do it as soon as possible（我的建议是大家应该尽快做这件事）
2）It looks that it is going to rain（看着天要下雨）
句子中的if。only 在此表示尚欠缺的唯一条件，if it can only be discovered 可以译为 只不过尚未被发现罢了。
9. This means the ability to face the facts as they are regardless of what one has previously1 thought.句子中的as是一个连词，表示方法，意思是根据；好似；比如
1）We must state the facts as they are.（大家需要如实地陈述事实）
2）Give me the bike as it is， I'll get it repaired （把自行车照实给我，我去维修）
Regardless of是一个常用词组，意思是不考虑，比如：
1）Our manager often acts regardless of consequences （大家经理做事常常不考虑后果）
2）He set out regardless of the heavy snow（他不考虑天降大雪出发了）
10.The worker in science must face facts whether they are pleasant or unpleasant.
whetheror引导的是一个让步状语从句，意思是无论，不管，比如：
1）Whether you believe it or not it's truth （无论你信不信，那一直事实）
2）He will be here on time whether he drives or takes the train
（不管他开汽车来还是乘火车来，他总会按时到达）
11.Scientists must be able to change their thinking and to adapt their theories to new facts as they are discovered.
adapt 意为使适应，使配合，常指改变以适应新的状况，后面常接介词to， 比如：
1）Some animals will modify2 their behavior to adapt to their environment（有的动物会改变习性来适应环境）
2）We have to adapt our thinking to the new conditions （大家得使我们的思想适应新的状况）
请注意不同动词adapt和adopt，在词语部分，大家已作了解说。
12. A scientific truth offers an explanation that is acceptable3 only in the light of what is known at a particular time
in the light of 是一个常用词组，意思是依据，根据；考虑到，比如：
1） To find truth in the light of science is the only correct way（凭着科学探求真理是唯一正确的办法）
2） We must apply Marxism in the light of China's specific conditions
（大家需要根据中国的具体状况应用马克思主义）
This should be discussed more fully4 in the light of the developments in the University
（考虑到学校的进步，这个问题应该讨论得更充分一些。）
本课主要词组
1. seek answers t
2. lay aside
3. be curious about
4. take apart
5. combine with
6. carry out
7. believe in
8. ergardless of
9. whetheror
10. be willing to
11. succeed in
12. in advance
13. adapt to
14. make up one's mind
15. once and for all
16. in the light of
17. respect for
18. come up
19. laugh at
20. change one's mind
21. experiment on
Text B solving problems scientifically
有用的词和词组 Useful words and expressions：
1. arouse5 one's curiosity6
once his curiosity is aroused7， he will try every means to make everything clear.
2. first of all
First of all I want to thank you with all my sincerity8.
3. arise
New problems will arise when old ones are solved.
4. result from
His failure resulted from his lack of experience.
5. bring about
The new policy has brought about a lot of changes in the rural9 areas.
6. in need of
I think we will be in need of your help soon.
7. build up
How can I build up my confidence when I meet failures time and again？
8. modify
Some animals will modify their behavior to adapt to new environment.
9. check with
I am not sure if these answers check with the key in the teacher's book.
10.turn out to be
His experiment turned out to be a great success.