GWD28-Q1,迷惘中的小羊。

1. GWD28-Q1:

Scientists claim that the discovery of the first authenticated mammal bones in amber could provide important clues of determining, in addition to how, when mammals colonized the islands of the West Indies.

1. of determining, in addition to how, when mammals colonized the islands of the West Indies

2. in the determination of how and when the islands of the West Indies were colonized by mammals

3. to determine how mammals colonized the islands of the West Indies and when they did[h1] 

4. for determining when the islands of the West Indies were colonized by mammals and how they were

5. for determining how and when mammals colonized the islands of the West Indies[h2] 

E, this was discussed before

在Pre语法笔记里，不是明确说 for doing 是错误的用法吗？

C才是对的

斑竹能提供一下这个题的讨论链接吗？

谢！

同意。