定語從句，絕對的雅思寫作高分作文必備。它可以把幾個充滿屌絲氣息的短句子瞬間連成一個高階大氣上檔次的長難句。它可以準確巧妙的對名詞或者名詞短語做出錦上添花的限定或者修飾。
為了寫出高分作文，首先我們需要來認識一下常見的關係代詞(relative pronouns)
who —— 用來指人
The students, who have acquired practical skills, can hunt for jobs in a short time.
Some people believe that innate talent is what differentiates a person who has been trained to play a sport or an instrument, from those who become good players.
As the policy would also affect the cost of public transport, it would be very unpopular with everyone who needs to travel on the roads.
which ——用來指物
France used coal as a source for only 25 units of electricity in 1980, which was matched by natural gas.
But by 2000 nuclear power, which was not used at all in Australia, had developed into the main source, producing almost 75% of electricity, at 126 units.
that ——用來指人或物
I personally think that some people do have talents that are probably inherited via their genes.
But there are various other measures that could be implemented that would have a huge effect on these problems.
It takes ten days for each egg to become a silkworm larva that feeds on mulberry leaves.
Find someone thatcan assist the students to improve their social skills.
where ——用來指地方
The biggest gender difference is at the lowest post-school level, where 90% of those who held a skilled vocational diploma were men.
when ——用來指時間
This cost decreased to only 5% of total expenditure in 1991 but rose dramatically in 2001 when it represented 23% of the school budget.
whose ——用來指所有
The result was a remarkably cohesive ensemble whose members seemed to have telepathic powers of communication.
Consumers, whose purchases account for about 70% of economic activity, face a variety of challenges.
why——用在the reason / reasons 後面
The pie chart shows the main reasons why agricultural land becomes less productive.
There are two important reasons why the Underground is safer than the overground railways.
限定性定語從句：
1.在名詞後面給出限定名詞的`資訊。
Find someone that can assist the students to improve their social skills.
2.如果沒有這些關係從句，所指的人，地點或物都是不清楚的。
Find someone that can assist the students to improve their social skills. (we do not know who)
3.關係代詞指的限定性關係從句中的賓語從句中的賓語時，可以省略。
Maybe there's a method (that) students can use.
非限定性定語從句從句：
1.給出事物額外資訊。
The students, who have acquired practical skills, can hunt for jobs in a short time.
2.不使用that
France used coal as a source for only 25 units of electricity in 1980, which was matched by natural gas.(which 不能換成that)。
3.必須要逗號來隔開從句和主句。
But by 2000 nuclear power, which was not used at all in Australia, had developed into the main source, producing almost 75% of electricity, at 126 units. (逗號不能省略)
4.不能省略關係代詞。
The biggest gender difference is at the lowest post-school level, where 90% of those who held a skilled vocational diploma were men. (not The biggest gender difference is at the lowest post-school level, 90% of those who held a skilled vocational diploma were men)
