相关简介
人教版高中英语必修一《Languages Around The World》Period Two PPT课件围绕语言词汇与语法展开，重点讲解“base”“date back”和“variety”三个核心知识点。课件通过例句、语境串记和特别提醒，帮助学习者掌握这些词汇的用法与搭配，并理解它们在不同语境中的含义与变化。以下为课件内容精要整理。
课堂新知讲练
1. base 动词与名词用法
base 作动词意为“以……为据点；以……为基础”，作名词意为“底部；根据”。释义：to have your main place of work, business, etc; foundation; bottom。
(P62) At the beginning, written Chinese was a picture-based language. 最初，书面汉语是一种以图形为基础的语言。
The movie is based on/upon the popular novel of the same name. 这部电影是以同名流行小说为基础（改编）的。
On the basis of my own experience, I made this decision. 我根据自己的经验做出了这个决定。
Access to justice is a basic right. 享有公正是一种基本权利。
【语境串记】
Basically, his income only meets basic living expenses. So he only chooses a simple lifestyle based on his limited salary. 基本上，他的收入只能满足基本的生活开支。所以他只会根据自己有限的薪水选择简单的生活方式。
2. date back (to…) 追溯到
(P62) It dates back several thousand years to the use of longgu—animal bones and shells on which symbols were carved by ancient Chinese people. 它可以追溯到几千年前龙骨的使用——古代中国人在动物骨头和贝壳上面刻画符号。
The history of the Great Wall can date back to/date from the Qin Dynasty. 长城的历史可以追溯到秦朝。
Should we set a date for the next meeting? 我们是不是该确定一下下次会议的日期呢？
The news you told me was out of date but you thought it was up to date. 你告诉我的新闻是过时的，但你却认为是最新的。
To date, we have received over 200 replies. 到目前为止，我们已收到200多封回信。
【特别提醒】
date from与date back to常用于一般现在时，不用于被动语态和进行时态，常用现在分词短语形式作后置定语。
3. variety 名词用法
variety 意为“（植物、语言等的）变体；异体；多样化”。释义：a type of thing, such as a plant or animal, that is different from others。
(P62) Over the years, the system developed into different forms, as it was a time when people were divided geographically, leading to many varieties of dialects and characters. 在随后的年代里，这一体系发展成了不同的形式。这是由于当时人们居住地域的分隔，从而导致不同的方言和汉字变体的产生。
Our customs vary from place to place. 我们的风俗习惯因地而异。
Salaries vary with various jobs. 薪水随各种各样的工作而异。
Everyone arrived late at the party for various reasons. 由于种种原因，每个人到达聚会都很晚。
