---what is john considering ? ---( ) his english, beacause h

A.
improving 动名词可以作 is considering 的宾语
完整的答语是：He is considering improving his English.to improve是不定式,不能作动词consider的宾语；improve是谓语动词形式,不能作宾语；having improved是动名词improving的完成形式,表明该动作先发于is considering的动作,故错误.