这个语法题的答案是不是错了？

Researchers agreed that the study of new treatments for heart attack patients was extremely important but more research was needed to determine that balloon angioplasty preceded with ultrasound was or was not any better for heart attack patients than the balloon procedure by itself.

1. more research was needed to determine that balloon angioplasty preceded with ultrasound was or was not any better for heart attack patients than
2. more research was needed for determining whether or not balloon angioplasty preceded by ultrasound is any better for heart attack patients than is
3. that more research was needed to determine whether balloon angioplasty preceded by ultrasound is any better for heart attack patients than
4. that more research was needed to determine that balloon angioplasty preceded with ultrasound was any better for heart attack patients than
5. that more research was needed for determining that balloon angioplasty preceded by ultrasound is or is not any better for heart attack patients than is

我选C 答案是B

我可以指出B的三个错误  1。 need for doing  错 2。whether or not 错 3。 is省略

看一下主体的结构。

如果是cde,感觉Researchers agreed that 。。。but that....有点怪，that后面的内容应该是researchers agree的内容。

而读下全文，but是作者的态度

另外，but是连词后面是要加完整的句子。cde翻了语法性的错误。

基本理解。 还是还想确认：

1。 than (is)...   这个is 是必须加， 还是可加可不加？？

2。 whether or not  这个用法可以吗？？？

1. than （do）属于可加可不加。

    eg.I run faster than you. 这里的you 后面do是可以省略的，因为不会有歧义

       若，monkeys climbe trees more quickly than elephants. 这里就有歧义，是猴子爬树比大象爬树快，还是猴子爬树速度比猴子爬象速度快?

             这里就应该修改为， monkeys climbe trees more quickly than elephants do/ do elephant.

    至此，你可以自己判断一下，这里的 than is...中的do属于可加还是不可加，不加是否会引起第二种理解。

2. Gmat语法不和现代英语语法冲突，whether or not在语法书中不属于错误。

      只是不简洁而以。 sc如果有语法错误首先排除，如果只是翻了不够简洁，在没有更好的选项可供选择的情况下可为正确答案。

      语法错误是不可能成为正确答案的 

弓虽