7. The reason for this was that he decided to orientate the map in the direction of the pole star since Polaris was the immovable guiding light in which the voyagers of the era placed their trust.

　　本句中，that引导的是一个表语从句。表语从句的结构为：

　　主语+连系动词+表语从句。表语从句也可用where， why， how引导。如：

　　1）The reason for his absence was that he was ill.（他缺席的原因是他病了。）

　　2）That was why I hated it.（这就是我不喜欢这个的原因。）

　　3）That is how he cheated people.（他就是用这种方式骗人的。）

　　Which所引导的是一个定语从句修饰guiding light限定性定语从句如果修饰“物”，关系代词that和which都可用，但在介词的后面只能用which，在口语中一般把介词放到从句后部去，这时则可以用that.如：

　　1）This is the question about which we had a discussion last night.（这就是我们昨晚讨论的问题。）

　　This is the question that we. Had a discussion about last night.

　　2）This is the fact on which we base our opinion.（我们的观点就是建立在这个事实之上的。）

　　This is the fact that we base our opinion on.

　　Trust在句中做名词用，place （put） trust in sb/sth 信任某人（某事）。

　　1）I don't have any trust in him.（我对他一点也不信任。）

　　2）Have some trust in the future everything will be OK.（对未来有点信心吧，一切都会好起来。）

　　3）The old lady placed great trust in her grandson.（那位老太太对她孙子非常信任。）

　　8. North at the top remained the accepted arrangement until the early Middle Ages， when the church began to interfere seriously with the advance of science.

　　本句中when引导一个由逗号把前面句子隔开的句子，其意思相当于at the time.如：

　　1）The party has been put off until next week， when we can get better prepared.（晚会被推迟到下周，那时我们能准备得更好些。）

　　2）We will wait have until 6， when the manager can spare us a few minutes.（我们在这儿等到6点，那时经理就能给我们几分钟了。）

　　Interfere with意思是“妨碍”，如：

　　1）Bad dietary habits often interfere with health.（不良的饮食习惯常常妨碍健康。）

　　2）The interests of the two countries do not interfere with each other.（这两国相互间没有利害冲突。）

　　9. Once again， north assumed its rightful place at the top of maps.

　　在第十五单元的Text B中，我们已经学过assume这个词

　　It has long been assumed that aggression is caused by male hormones.（长期以来，人们认定好斗是由男性荷尔蒙引起的。）

　　在本句中assume的意思是acquire（获得，取得）

　　请注意下列例句中assume的意思：

　　1）I assume the misunderstanding will be cleared up.（我认定这误会会消除。）

　　2）He assumed the report to be unreliable.（他猜那报告不可靠。）

　　3）Farmers will have a good harvest ， assuming that the weather is favorable.（假如风调雨顺，农民将会有好收成。）

　　4）Who will assume the costs of running a school？ （谁来负担开设一所学校的费用？）

　　5）He assumed a leading position last May.（去年五月，他担任领导职务。）

　　6）Hitler assumed power in 1933.（希特勒于1933年夺得政权。）

　　7）He assumed full control of the company.（他完全控制了这家公司。）

　　本课主要词组

　　1. in the sense of　　　　　　　2. more than

　　3. be based on　　　　　　　　　4. rather than

　　5. attempt to do sth　　　 　　 6. in the form of

　　7. in search of　　　　　 　　　8. at the top

　　9. in the direction of　　 　　 10. place trust in

　　11. interfere with　　　　　　　12. in accordance with

　　13. from…point of view　 　　　14. reliance on

　　Text B    You Have a Choice

　　短语表达

　　1. side by side

　　They are sitting side by side.

　　We walked side by side along the river.

　　2. be seated

　　Please be seated， I will fix you a cup of coffee.

　　The hostess was seated with the guests when I hurried in.

　　3. ahead of

　　The boy is running ahead of his classmates.

　　I believe we can finish the work ahead of time.

　　4. be certain of

　　I cannot be certain of the time of their arrival.

　　Can you be certain of the truth of his utterance？

　　5. bring about

　　The new policy is sure to bring about a lot of changes.

　　What Father said has brought about a profound change in his personality.

　　6. account for

　　This excuse cannot account for your absence.

　　Her explanation doesn't account for the failure.

　　7. regardless of

　　All of you will be given a chance regardless of your age and sex.

　　Regardless of which method you choose， the result will be the same.

　　8. make a difference

　　Whether he comes or not will not make any difference.

　　I hope my participation will make a difference.

　　9. lead to

　　Excessive smoking may lead to lung cancer.

　　The misunderstanding led to a bad quarrel.

　　10. pull out of

　　The train pulled out of the station at 10：00.

　　When do you think the car will pull out of the garage？

　　11. for sure

　　I don't know for sure who will be in charge of this department.

　　He couldn't tell for sure what was in the distance.

　　12. apply to

　　It is hard to apply the rule to real work.

　　It is necessary that the theory be applied to practice.

　　13. deal with

　　He is hard to deal with.

　　I have no idea how to deal with this situation.