刚 literally means "just now" (refers to time). 我刚吃了午饭。I had lunch just now. 就 can mean A LOT, so I don't know how to make one single example to explain it, sorry :P But basically, 就 is used to emphasise or causal relationship. the following links are all right about 就, you might be interested in having a look. 1. http://answers.echineselearning.com/questions/2010-06/29/165319959WECRSTPI.html 2. http://mandarin.about.com/od/particles/a/Jiu-Mandarin-Particle.htm 3. http://www.chinese-forums.com/index.php?/topic/3036-grammar-1-%E5%B0%B1/ 4. http://www.ctcfl.ox.ac.uk/Grammar%20exercises/Jiu%20&%20Cai.htm 才 means "only" often refers to time, but it can refers to any other general things too. example for referring to time: 现在才下午三点。 Now it is only 3 o'clock in the afternoon. example for general: 他才三岁。 He is only three years old. 只 literally means "only", using the same example as 才. 他只有三岁 is the same as 他才三岁。 my answer might not be sufficient, but I hope it could help you a bit.

他刚回来！你就来了！只是没有想到才短短几分钟时间！

你刚回来？--just 你就回来了？---only 你才回来？---you are so late 就只有你回来了？---only you？