请教GWD15 Q1

wildbean

?1. GWD21-Q1:

?According to analysts, an alliance between three major personal computer companies and most of the nation’s largest local telephone companies would enable customers to receive internet data over regular telephone lines with speeds much higher than is currently possible.

A.with speeds much higher than is

B.with speeds that are much higher than are

C.at much higher speeds as are

D.at much higher speeds than that

E.at speeds much higher than are

不明白为什么than后面要加are,望大家指点

达达尼昂

一种理解是，than后面应该是speeds are urrently possible,如果不加are后面的currently possible就没有系动词了
另一种than和as有指代比较成分主语的作用，这里的than就有指代“speeds”的作用

wildbean

嗯，明白了，Thank you