适用于：人教课标高二英语下学期选修8 Unit2 Grammar新授课课件

On the one hand, the whole scientific world followed the progress of the first successful clone, Dolly the sheep.
The fact that she seemed to develop normally was very encouraging.
Then came the disturbing news that Dolly had become seriously ill.
Altogether Dolly lived six and a half years, half the length of the life of the original sheep.
同位语是句子成分的一种, 它位于名词、代词后面, 说明它们的性质和情况, 它可以由名词、代词、名词性短语或从句充当。
同位语的表现形式有以下几种：
(1) 名词    (2) 代词    (3) 数词    (4) 从句
(5) 由such as, that is引导
    Some subjects, such as maths and physics, are very difficult to learn.  
     某些学科, 例如数学和物理, 是很难学的。
(6) 由of引导
    The city of Beijing has been greatly changed since 2000. 自从2000年以来,
    北京市发生了很大的变化。