问大全里的一道题 regard n. as后面可以用-ing?

stellina

Most nations regard their airspace as extending upwardas high as an aircraft can fly; no specific altitude, however, has beenofficially recognized as a boundary.
(A) as extending
(B) as the extent
(C) to be anextent
(D) to be anextension（A）
(E) to extend
因为把做对的题目都删掉了，所以就不知道题号了。这道题答案给的选A，但是我想知道可以用regard n. as -ing可以这样吗？？？
请指教，谢谢！

wenchang

这里的结构不是regard as结构，而是as ... as结构