We may find that learning a foreign language does not have to be learning our mother tong

问题补充：

We may find that learning a foreign language does not have to be learning our mother tongue, but can in fact be as easy.

A. twice harder as

B. as twice hard as

C. twice as hard as

D. as twice hard

答案：

A. twice harder as

B. as twice hard as

(答案→)C. twice as hard as

D. as twice hard

解析：

这题考查倍数的表达，倍数+as adj as的用法，A项应该是twice harder than，C、D项都是顺序错了，选C。