别开生面having sth. New

别有用心have ulterior motives

彬彬有礼refined and courteous urbane

兵不厌诈in war nothing is too deceitful

博古通今erudite and informed

不败之地incincible position

不耻下问feel not ashamed to learn from one's subordinates

不可救药be past praying for beyond redemption

不劳而获reap where one has not sown

不屈不挠fortitude indefatigability perseverance persevere tenacity

不速之客crasher uninvited guest

不同凡响outstanding

不言而喻speak for itself tell its own story tell its own tale went without saying

不遗余力spare no effort spare no pains

不以为然not approve object to

不义之财filthy lucre filthy pelf the mammon of unrighteousness

不亦乐乎extremely

不远千里go to the trouble of traveling a long distance

不约而同happen to coincide