prep2-80 改变原意?

(A) Although at one time children's programming had been limited to a few hours a week, now,

however, there are at least four cable networks that dedicate themselves

(B) With children's programming having been limited at one time to a few hours a week, now at

least four cable networks have dedicated themselves

(C) Once limited to a few hours a week, there are now at least four cable networks with children's

programming that dedicate themselves

(D) Children's programming was once limited to a few hours a week, but now there are at least four

cable networks dedicated

(E) While children's programming had once been limited to a few hours a week, at least four cable

networks are now dedicated

(D)

为什么不选 E?

语法注释上的解释

这两个时态之间就存在过去的时间点这一断层，即过去完成时使用错误

不懂啊？

原句使用让步状语，并且使用过去完成时态，E 也使用让步状语和过去完成时态，而 D 改成了两个并列主句的强转折和过去时而且还用了 there be 这种长错句型。怎么看 D 都是改变了原意啊。由让步转折变为强转折也没改变原意？

大家再看看 E 还有什么其他错误？

老外和你有同样的困惑...

A) Past perfect 'had been limited' is wrong. Since the phrase begins with 'Although', 'however' is redundant.
B) Present perfect 'Having been limited' is wrong. The limit no longer exists.
C) Misplaced Modifer. 'Once limited to ...' should refer to children's programming.
D) Correct - Tense is correct. We have two independent clauses joined by coordinating conjunction 'but'.

choice e is incorrect because of its inappropriate use of the past perfect. if you're going to say kids' programming had once been limited to ..., then you must reference a second past event. this sentence doesn't do that: the second event referenced is in the present (specifically, 'now').

以上解释引用自http://www.manhattangmat.com/forums/although-at-one-time-children-s-programming-had-been-t2128.html

因为过去完成时是过去的过去 题目里没有一个有效的过去时来承接

让步状语用过去时就可以了

PS:过去完成时是一个比较高级的语法  一般不到最后不考虑这个时态的错误

要的就是这个承接

顺便问一下，D 逗号前后不是两个完整的句子么？为什么可以用逗号连接？

其实再看看，D并没有改变句子中心

although A，B  中心在B

A，but B 中心在B

一样的。

我只是惊奇于there be在这里竟然对了，我一般看到there be就跳过。。。

只能说时态问题比较严重...