选修9 Unit 2一、词汇知识1．mercy n. 怜悯；宽恕；仁慈；幸运，侥幸at the mercy of 任……摆布，受……支配（1）Gone are the days when we were at the mercy of the weather .我们靠天气吃饭的日子一去不复返了。
（2）I’m not going to put myself at the mercy of the bank . 我不想任由银行摆布。
show mercy to sb. 对某人表示怜悯＝have mercy on/upon sb.They are praying God to have mercy on them.without mercy 残忍地 beg (for)/ask for mercy 乞求/请求原谅It’s a mercy that …幸亏…It’s a mercy that she wasn’t seriously hurt.2．horizon n. 地平线；视野，眼界on/below the horizon 在地平线上/下broaden/widen one’s horizons 开阔眼界，拓宽视野She wanted to travel to broaden / widen her horizons.3．nowhere adv. 无处，哪里都不nowhere else 没有别的地方Nowhere else can you find a more beautiful place.get/go nowhere（使）无进展或一事无成It’s a good idea but it will get nowhere without more financial support.这个主意不错，但如果没有更多的财政支持是不会成功的。
nowhere to be found/seen/nowhere in sight 不可能找到或看见The children were nowhere to be seen .nowhere near 离…远；根本不，远不（如）(1) He lives nowhere near London .(2) John is nowhere near as fit as I am . 约翰远不如我健康。
4．reference n. 参考make reference to sb./sth. 提到，说到He made no reference to what happened to him yesterday .for reference 作为参考/查阅I put down his telephone number for future reference .我记下了他的电话号码以备将来用得着。
in/with reference to 关于 reference book 参考书；工具书refer vi. 谈到，涉及refer to 谈到，提起；涉及，与……有关；参考，查阅refer to sb./sth. as…把…称作…refer… to…将…送交给…（以求获得帮助等）(1) My doctor referred me to a specialist . 我的医生让我去找一位专家诊治。
(2) The case was referred to the Court of Appeal . 这个案子被送交到上诉法院。
5．update vt. 更新；改造；使现代化update sth. 更新/改进某物We advise you to update the software . 我们建议你对软件进行升级。
update sb. on sth . 向某人提供关于某事的最新信息I called the office to update them on the day’s development .我给办公室打电话告诉他们当天最新的发展。
6．tendency n. 倾向；趋势have a tendency to do sth. 倾向于做某事，往往会做某事He has a tendency to talk much when drunk . 他喝醉了酒往往唠叨。
have a tendency to/towards 有……的倾向She has a strong natural tendency towards caution . 她天生喜欢小心谨慎。
There is a(n) growing/increasing tendency for sb. to do sth .There is a growing tendency for people to work at home instead of in offices.人们越来越倾向于在家而不是在办公室工作。
tend vi. 往往会；走向；趋向tend to do sth. 易于做某事，往往会做某事Women tend to live longer than men.tend to/towards 有…的倾向His views tend towards the extreme . 他的观点趋于偏激。
7．deposit vt. 放；（把钱）存入银行 n. 订金，押金；存款(1)Now people seldom deposit their money and valuables in their home safe .现在人们很少把钱和贵重物品放在自家的保险柜里。
(2)I deposited 200 dollars in my account this morning .pay a deposit on sth. 付某物的订金/押金make a deposit 存款 eg.I’d like to make a deposit.8．thirst n. 渴，口渴；渴望 v. 感到口渴，渴望，渴求a thirst for knowledge/power etc . 对知识/权力等的渴望thirst (vi.) for sth. 渴望，渴求（某物）thirsty adj.口渴的；渴望的 be thirsty for sth. 渴望，渴求某物9．tear v. 撕破；扯破 (tore—torn)Take care ! The paper tears easily . 当心！这纸很容易撕破的。
tear up 撕碎tear apart 撕开，扯开tear at 撕扯The children were screaming and tearing at each other’s hair.孩子们尖叫着，互相抓扯着对方的头发。
tear down 拆除，推倒(=pull down ) eg.The old house was torn down.tear oneself away from 依依不舍地离开；忍痛割舍The girl was unable to tear herself away from TV though her mother asked her to have dinner .tear n. （常用复数）眼泪in tears 含泪，流着眼泪 burst into tears 大哭起来move sb. to tears感动得某人流泪be close to tears 眼泪快要夺眶而出二、难句剖析1．We may well wonder how seamen explored the oceans before latitude and longitude made it possible to plot a ship’s position on a map.（P.12）我们很可能感到奇怪，在经纬度被用来在地图上标出船只位置之前，海员是如何对海洋进行探索的。
may well do sth. “很可能做某事”,相当于be very likely to do。
(1)She may well refuse to talk to you.(2)Her appearance has changed so much that you may well not recognize her.句型：sth. makes it possible to do sth.The development of transportation makes it possible for us to go wherever we want to. 交通的发展使得我们想去哪里就去哪里成为可能。
plot在此句中意为“（在地图上）画出，标出”。
2．Nobody knew that the earth turns eastwards at about 15 degrees every hour ,but sailors did know an approximate method of calculating longitude using speed and time .（P.13）以前没有人知道地球每小时向东移大约15度，然而海员们确实知道用速度和时间来计算经度的近似标准的方法。
句中did表强调，using speed and time现在分词短语作方式状语。
3．The earliest, the astrolabe, was a special all-in-one tool for telling the position of the ship in relation to the sun and various stars which covered the whole sky. (P.13)最早的是星盘，它是一种特殊的集多种功能于一体的工具，它可以用来表明船只同太阳和布满天空的各种星星之间的相关位置。
其中the astrolabe 作the earliest的同位语;which引导定语从句修饰various stars; all-in-one意为“多功能的，多用途的”；in relation to在此句中意为“和…相比”。
in relation to和…相比；关于(1) Wages are very low in relation to the cost of living.和生活费相比，工资是低的。
(2) I have some comments to make in relation to this matter.关于这件事，我有点看法。
4．However,it was awkward to use as one of the points of reference was the moving ship itself. (P.13)但是，它不容易使用，因为其参照点之一就是行驶中的船只本身。