So , me chiah and bernard tried to fix it.. We bought a new cover and replaced it.. We off the main switch and changed it. Before we changed, We used testpen to test the current and actually we didn't realize that the testpen is actually spoiled which means the current is still there. For the 1st time, we re-on the main switch and we heard the sound "pop" and the switch automatically turned off.. So we realize that something went wrong already. So we Off the main switch again, however this time, the fan can operate, so it meant that something going wrong, thus we decided to separate the wires without touching each others..
So before we do it, I used testpen(spoiled one) to test it and obviously it showing no current, So I used plier to separate it, And very unlucky, I got shocked, somehow i felt the current moving to my hand, thus I throwed the plier.Luckily the current is not that great , else better say 88 to me..
Next, we asked the maintenance people came and fix but they said something wrong with the wires and must until Monday. So right now were just used the cellophane tape to cover it..
In conclusion, as a future enginner, we must have a functional testpen when we fix those electrical stuffs..