TTGWD23-13请问!! D明明很工整平行啊

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

为什么是A 呢?

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

后面为什么用ＣＯＵＬＤ　而前面是ＭＡＫＥＳ呢．谢谢．

否定应该用NOT SO... AS吧……

好像记得这么回事

so ^^^as to有表目的的意思

这里不用

Ar後方省略it is not,故意義成立.could意義表"並不一定會造成結果"不須改成causes

Br後面不平行多as

C:沒有enough so 的用法

D:as adj as 是比較用法不是表目的

E:too adj to V 是固定用語在此不該以Ving代替