do a good job 好好干;干得好
join hands with 互相合作，携起手来
join in 参加(活动)
join up 参军，入伍;联合起来
play a joke on sb. 开某人的玩笑
judging by 从…判断
jump at 急忙接受，立即抓住
jump off 开始，开始进攻
just about 差不多，几乎
just as 正象;正当…的时候
just the same 完全一样
do justice 公平对待;和…酷似
From:https://www.zgghmh.com/CET-6/20006433.asp