请教一道语法题GWD-23-Q13

Karen点点

GWD-23-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.

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

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

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

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

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

这道题选A哎，可是为什么D不对呢？前后两个it应该都是指的granitic soil吧，这样的话跟前面那个it就是同一主语啊，为什么D不对

nesstang

同意楼上，我记得是说，老师以前说过否定可以用so...as to....不代表as ...as to 不能用在否定句

ljhewuxia

其实否定也可以用as....as

xuromeo

为什么a里面可以用it could?时态对么

酱子啊

as...as to...结构用于陈述句肯定结构，否定结构需要用so...as to...