One reason that can cause the refill tube to keep flowing is the flush lever is not working. There are complete toilet repair kits for sale at Home Depot.
Again, this is a common problem, can be easily fixed.
TYPO ba, 太慢了is too full le, not too slow le.
There is a pipe in the tank, if the water level above the top of the pipe, the water will 往马桶里流 through that pipe.