一、Reading
Australia is a unique country. It's the world's largest island, but it's also the world's smallest continent. In fact. Australia is the only country that is also a continent. It's about the size of the United States, but it has a population of only 16.5 million. If it sounds like an interesting place to visit, that's because it is.
二、解析
■ Australia is a unique country.
- 主：Australia
- 系：is
- 定：a unique
- 表：country.
■ It's the world's largest island, but it's also the world's smallest continent.
- 主：It
- 系：is
- 定：the world's largest（最高级）
- 表：island
- 并列连词：but
- 主：it
- 系：is
- 状：also
- 定：the world's smallest（最高级）
- 表：continent.
■ In fact. Australia is the only country that is also a continent.
- 状：In fact.
- 主：Australia
- 系：is
- 定：the only（唯一的）
- 表：country
- 定从：that is also a continent.
- 关系代词、主：that
- 系：is
- 状：also
- 表：a continent.
本句中的 that 是关系代词，理论上等于 which，但因之前的名词用 the only 来修饰，故此处公能使用 that。
必须使用 that 取代关系代词 who、whom、which：
（1）在有最高级形容词修饰的名词之后。
（2）在有 the only 修饰的名词之后。
（3）在有序数词（如 the first、the second...the last）修饰的名词之后。
■ It's about the size of the United States, but it has a population of only 16.5 million.
= It's about as large as the United States,...
- 主：It
- 系：is
- 表：about the size of the United States,
- 连：but
- 主：it
- 谓：has
- 宾：a population
- 后定：of only 16.5 million.
the size of：若在 be 动词之后，就等于 as large as。第一个 as 为副词，修饰形容词 large，第二个 as 连接词，译成 “和”。
be the size of：与...一般大小（一样大）
about：adv.大约，通常用于修饰数字。
■ If it sounds like an interesting place to visit, that's because it is.
= ...,that's because it is（an interesting place to visit）,避免与主句重复所以省略。
- 条件状从：If it sounds like an interesting place to visit
- 引导词：If
- 主：it
- 谓：sounds like
- 宾：an interesting place
- 后定：to visit
- 主：that
- 系：is
- 表从：because it is.
sounds like + 名词：听起来像...
“That is because...” 句型中从属连词 because 引导的名词性从句在此作表语，这也是个常用句型，意为“这就是为什么……/因为……”。
“That is because...”与“That is why...”之间的不同在于“That is because...”指原因或理由，“That is why...”则指由于各种原因所造成的后果，例如：
He did not see the film last night. That is because he had to help his little sister with her homework.
昨天晚上他没有去看电影， 那是因为他得帮助他的妹妹做作业。（第一句话说明结果， 第二句话说明原因）
He had seen the film before. That is why he did not see it last night.
他以前曾看过那部电影， 因此他昨天晚上没有去看。（第一句话说明原因， 第二句话说明结果）
三、语法
本课主要语法：
（1）知觉动词之后应置形容词作主语补足语。
（2）知觉动词后亦置 like（像），此时 like 为介词，之后再置名词作其宾语。
（3）关系代词 that 的使用时机。
详见课本描述。