下面两题百思不得其解，望大虾指点。

one of sth.的中心词是one还是sth.？

With its abundance of noun inflections, Icelandic is one of several Germanic languages that is compact when written but can lengthen considerably when translated into English.fficeffice" />

(A) is compact when written but can lengthen considerably when translated into English

(B) are compact when they are written, but they can lengthen considerably when they are translated in English

(C) is compact when written but can lengthen considerably when being translated into English

(D) are compact when written but can lengthen considerably in English translation

(E) is compact when it is written but can lengthen considerably when translated in English

下面这题的从句中的主语指代谁？

For most consumers, the price of automobile insurance continues to rise annually, even if free of damage claims and moving violations.

(A) even if

(B) despite being

(C) even if they are

(D) although they may be

(E) even if remaining

答案是DC，我的选项是AB。答案有问题吗？