天山 5-28

sandiegotj

Obviously,D

Speaking of using past perfect tense in the answer D, I got some grammer explanations for you

	The present perfect is used when the time period has not finished:
I have seen three movies this week. (This week has not finished yet.)
	The present perfect is often used when the time is not mentioned:
Gerry has failed his exam again.
	The present perfect is often used when the time is recent:
Ikuko has just arrived in Victoria.
	The present perfect is often used with for and since.
Greg has lived here for 20 years. Greg has lived here since 1978.

[此贴子已经被作者于2005-9-2 0:24:15编辑过]

benjaminshufe

这道题也是天山3里面的第17题，是不是应该beautywawa excel版本的答案也改下

scorp_w

D  铁一般的事实

mymengming

到底是什么使sloth成为...最早知道的哺乳动物呢？是化石发现的时候还是其年代？显然是其年代。A与D的区别就是两个修饰成分的限定与否的互换。
A中的错误：第２个was和that was并列，句子没谓语，而且平行缺and
E中的句子就更离谱了，唉！
当时去掉C就是因为那个完成时
A，it指代不清，似乎指代fossils，逻辑意思不正确，and前的逗号错
B，they没有指代对象，it问题同A
C，两个was都错，导致句子逻辑意思不正确
D ，is the best，making the sloth ...用sloth明确对象是ETS常用的正确形式，现在完成时表示到目前为止，已经发生
E，sloth which逻辑意义不对。
总结：一般前面是个句子，后面用分词状语从句伴随表结果等经常是正确的选项