Q13:

Researchers hypothesize that granitic soil is the ideal construction material for the desert tortoise because it is not so hard that it makes burrowing difficult or so soft that it could cause tunnels to collapse.

1. so hard that it makes burrowing difficult or so soft that it could cause

2. hard enough to make burrowing difficult or soft enough as to cause

3. so hard as to make burrowing difficult or soft enough so it causes

4. as hard as to make burrowing difficult or as soft as to cause

5. too hard, making burrowing difficult, nor too soft, so as to cause

此题标准答案c，但是我觉得c不是很好。首先感觉or前后部分不很对称。其次觉得enough意思和此处要表达的意思有些差别。我选a。

欢迎诸位讨论，先谢过了！

up d.

c has the wrong gmat paradigm" enough to do" or "something enough"

and the "it" after "so" has no referent

我想问问bipedalisms，哪儿下载ＧＷＤ１３套之后的题啊，谢了

感谢解答。d看上去不错，但我有点疑问。我记得否定后面要用so..而不是as...as。其实，我也觉得a有点啰嗦。