Jack¹ of all trades 似乎什么都懂的人
　　jolly dog（guy） 乐天派

　　jump on sb 向某人乱发脾气

　　jump the battery 充电

　　jumping the gun 迫不及待

　　just a minute 等一等；就来了；且慢

　　just as well 不如做某事也可

　　Just as you say. 好吧，随你的便

　　just follow suit 照办；跟进去

　　just for the fun of it 只不过好奇罢了

　　just the ticket， be 正是所需的

　　just too bad 太可惜；真糟糕

　　just what the doctor ordered 正合我的心意

　　keep a running account of 把教授在课堂讲的内容都记下来

　　keep a straight face 忍住不笑出来

　　keep an eye on 留意

　　keep an eye on sth 密切注意

　　keep body and soul together 继续活下去

　　keep company 陪伴

　　keep in touch with 联系

　　keep it to yourself 保密

　　keep it under your hat 保密

　　keep my fingers crossed 交叉手指，乞求某事成功

　　keep one's head 镇定

　　keep one's head above water 活下去

　　keep one's nose to the grand stone 孜孜工作

　　keep one's shirt on 不动手打架

　　keep pace with 保持同步

　　keep punching 继续努力