justify后加doing。
因为它是（及物动词，后接名词、代词或动名词）“表明或证明（某人/某事）是正当的、有理的或公正的”：
Such action can be justified on the grounds of greater efficiency.以提高功效为依据可以证明采取这种措施是正确的。
You shouldn't attempt to justify yourself.你不应想方设法证明自己有理。
You can't justify neglecting your wife and children.你不关心妻子儿女是说不过去的。
