We use the word “過” to describe events happened in the past. As mentioned before, we will use the word “沒有” to express a negative meaning. However, to emphasis something that we have not done, we use the word “waan4 mut6 jau5” (還沒有) to express that sense instead. Sometimes, “waan4 mut6 jau5” (還沒有) can imply that one is going to so something in the future. If this is the case, some people prefer using “mei6” (未) to “mut6 jau5” (沒有).