98-1-13 求助

13. ____ usually thought to end in northern New Mexico, the Rocky Mountains really

extend southward to the frontier of Mexico.

(A) Despite

(B) To be

(C) While

(D) However

答案：C

这里however 为何不可以呢？引导一个过去分词做状语？

However 是一个转折的连词，这里在语义上面好像有不太对，而且however跟while不同，while的用法比较多样，however比较死板，必须完整的用。