an ancient 音标是：[ən 'eɪnʃ(ə)nt] 连读可读作：[ə 'neɪnʃ(ə)nt]，最好是读作[ən 'neɪnʃ(ə)nt]。

This is an ancient shell that my mother gave me a long time ago.

这是很久以前我妈妈送给我的一只古老的贝壳。

that的用法：

此处是由关系代词that引导的定语从句，修饰先行词an ancient shell。that在定语从句中作直接宾语，还原一下此定语从句的结构就是：My mother gave me an ancient shell a long time ago.

当先行词是指物的名词或代词时，引导词可用that或which。当that或which在定语从句中做宾语时，that或which可以省略不写。由此本句还可以表述为：

This is an ancient shell which my mother gave me a long time ago.

This is an ancient shell my mother gave me a long time ago.

所谓先行词：定语从句所修饰、限定的词叫先行词。

作定语的句子就叫作定语从句。

定语从句通常跟在和它发生关系的先行词之后，它与先行词有着不可分割的联系。 它通常是由关系代词(who，whom， whose，that，which，as)和关系副词(where，when，why， how)来引导。

1、先行词指人时，引导词可用Who，Whom及that，其中当引导词在句中作主语时用Who或that；当其充当宾语时用whom或that，在非正式宾语中也可用who，也可省略。

a. That boy who/that broke the window is called Tom.

b. The person to whom you just talked is Mr Li.

b 句可改为：The person(that/whom/who)you just talked to is Mr Li.

2、先行词指物时，引导词用that或which

a. They planted the trees which didn’t need much water.

b. The fish (which)we bought were not fresh.

3、先行词指时间时，引导词用When/on which或in which

a. I still remember the day when/on which I first came to Bei jing.

b. I'll never forget the year when/ on which we worked on the farm.

4、先行词指地点时，引导词用Where或in which

This is the house where/in which we lived last year.

或：This is the house that/which we lived in last year.

5、whose在定语从句中作定语时，可用来指人，也可以用来指物，如:

a. This is the boy whose mother died a month ago.

b. This is the house whose windows were broken.此句可改成：

This is the house the windoues of which were broken.

6、先行词表示原因时，引导词用why,如:

The reason why he was late for school was that he had been knocked down by a bike.

二、物殊情况：

尽管有以上基本原则，但要学好定语从句更应注意以下特殊情况；

Ⅰ、当定语从句的先行词为表示人的不定代词，如： anyone,anybody,everyone,everybody,noone,nobody,all， these ，those等时,用who而不用that

Those who break the rule are pulished.

Anybody who had eyes could see the elephant was like a snake.

Ⅱ.以who或which作主语的特殊疑问句中先行词指人，引导词只用That，如:

a. Who is the person that is standing at the gate ?

b. Which of you that knows something about English doesn’t know this word?

Ⅲ、先行词指物时引导词用that而不用which的情况:

1. 先行词有序数词或形容词最高级修饰时，

This is the best composition that has been written in English.

2. 先行词是all,something,anything,nothing,everything,little,few,much等不定代词时

There is nothing/little/much that we can do for her.

3. 先行词被all,every,no,some,any,little,much等修饰时

I’ve read all the books that you gave me.

4. 先行词被the only/very等修饰时

This is the very/last place that they visited yesterday.

5. 有两个以上先行词，分别表示人或物时

They talked about the teachers and the schools that they had visited.

6. 先行词为基数时

Yesterday I caught two fish,Now you can see the two that are still alive in a basin of water.

Ⅳ. time为先行词时，前边如有序数词修饰时，定语从句引导词用that或什么也不用，如没序数词修饰时，用when或that均可

This is the last time(that)I shall give you a lesson.