J
jack of all trades 博而不精的`人，万事通
join in 参加，参与
jump to a conclusion 贸然断定;过早下结论
just as well 无所谓，也好
justify in doing sth 有理由做某事
K
keep an eye on 照看，注意，观察
know/learn the ropes 了解、掌握做事情的技能!
keep body and soul together 生存下去
keep in touch with 与通信，保持联系
keep ones head 保持镇静
keep sb. informed 及时通知某人
keep sth. in good order 使处于良好状态，使井井有条
keen on 喜好
kill time 消磨时光
keeping up with the Joneses 老和别人攀比
学识谷
