justify: may be preferred when the stress is on providing grounds that satisfies conscience as well as reason: an end that surely did not ~ such harsh means.


warrant: is especially appropriate when the emphasis is on something that requires an explanation or reason rather than an excuse, and is likely to suggest support by the authority of  precedent, experience or logic: the deposits have shown enough ore to ~ further testing. (注意是warrant不是warrent)


justify: 符合道理和良知，warrant: 提供理由和解释，有先例经验逻辑。


记忆方法: 1） JW觉悟




   2） 理应的意思是有足够根据做某事mean to be what constitutes sufficient grounds for doing, using, saying or preferring something.