问题补充：
He apologized for .
A. his not being able to come
B. his being not able to come
C. his being able not to come
D. him not being able to come
答案：
(答案→)A. his not being able to come
B. his being not able to come
C. his being able not to come
D. him not being able to come
解析：考查动名词复合结构。For是介词，后面接动名词。动名词复合结构中not放在doing前面,所有格放在not前。句意：因为没有能来他向我道歉。
