补充一下lz所说的第一点:限制性定语从句（“that”）和非限制性定语从句（“，which”）的区别。所谓限制性定语从句就是能够缩小前面被修饰词的范围的（the elephant that gave rides to children at the Whipsnade Zoo从泛指的elephant，到公园里给人骑的elephant，缩小了范围）；而非限制性定语从句不会缩小被修饰词的范围（the elephant, giving rides to children at the Whipsnade Zoo, 给人的感觉是所有的elephant都是在公园里被人骑的）。在判断时要关注句子的逻辑意思。

this doesn't make sense -- "the elephant", alone, would not be a valid reference, and we need to be told that it was specifically the elephant that gave rides to the children (and not some other elephant). for both of these reasons, the modifier must be an essential (not set off by commas) modifier.

note A as B: A = that the elephant ... was earning ... what she then earned as director ...; B = a example of ...， 将动物园大象挣的钱跟她当director挣的钱一样多（这个事情）看做一个收入不均的例子。
A和B是定语和状语的区别，应该用定语对大象做限制性修饰，指出是“驼人”的大象。
C将“有大象”的事情当做“例子”， D E将“大象”当做“例子”。

AC 区分
首先应该是一个现象作为例子而不是一个名词，所以DE错误
B时态不对
C and 前后并列的句子已经是“做例子”和“它挣得和she一样多”，不平衡

（B）选项
,giving引导非限制定定语从句，是对大象特性的补充说明，指的是所有动物园的大象是给孩子骑得
显然B在逻辑上不正确，能被孩子骑得大象只是动物园中大象的一小部分
同时过去完成时不对

过去完成时：
1、表示过去的过去。要使用过去完成时，要求句子里有一个一般过去式动词，或者一个过去的时间词语发生在过去完成时的动作之后。
eg.:
(1)The film had started by the time we arrived at the theater.
film had started在先，然后We arrived
(2)By 1945, the United States had been at war for several years.
1945是过去的时间，had been at war发生在1945年之前

2、过去完成时不强制要求动作本身的持续。
eg.:
The teacher thought that Jimmy had cheated on the exam.
He had cheated在先，然后teacher though he had cheated。
3、只要表达清晰，事件发生的顺序无歧义，过去的过去的动作也可以用一般过去时。如有before、after说明事件的先后顺序，不必用过去完成时had done来描述事件发生顺序。
eg.: Laura locked the deadbolt before she left for work.

note the elephant that gave rides to children at the Whipsnade Zoo was earning......as example

Note that… as…

choice (b): the modifier shouldn't be a nonessential modifier.
right now the modifier ("giving rides to children at the Whipsnade Zoo") is set off by commas, indicating that it can be removed from the sentence with no loss of meaning.

A that引导限制性定语从句，特制动物园中那些可以给孩子骑的大象
B ,giving引导非限制定定语从句，是对大象特性的补充说明，指的是所有动物园的大象是给孩子骑得
显然B在逻辑上不正确，能被孩子骑得大象只是动物园中大象的一小部分

then 除了表示之后，主要是表示“在当时”的和轻微的因果关系：“由此”

In B, the structure of noted... that the elephant, giving rides ..., had been earning falsely implies that the reader already knows about the elephant--that is, that the existence of this particular elephant is not new information. Also, the past perfect had been improperly places the elephant's earning in the past, prior to Wootton's; consistent verb tense is needed to show that the actions are simultaneous.

OG10:　　Choice A, the best answer, uses the idiomatic construction noted... that and clearly focuses on the salient information-- a comparison of annual earnings.

有两点不明白：1/ 主句未划线部分应该是be noted as吧？ 2/ 划线部分为什么用过去进行时the elephant was earning? 用一般过去时更合适吧