但什么时候看成动名词什么时候看成动词的ing形式很混乱,求大侠解释。。。 Most nations regard their airspace as extending upward as high as an aircraft can fly; no specific altitude, however, has been officially recognized as a boundary.
(A) as extending
(B) as the extent
(C) to be an extent
(D) to be an extension
(E) to extend 比如这道题A优于B就是因为extend动词优于名词 为什么extending不看成动名词呢?