The general toilet is not flushed and there is still water in the toilet sink

That's right. That's the principle of the feed-through, which prevents the smell of the sewer from coming up!

Answer, no, there is no good quality here, otherwise it is easy to breed bacteria.

Generally, there should be some clear water left in it after inhaling it, but there will not be a lot of water left, if you don't go down, press the button that puts more water to see if it is not successful, hold it for a few seconds and then let go.

It is not estimated that the type is wrong, and the toilet is divided into front and back.

Also, the toilet pit distance is not right, resulting in misalignment.

In siphon technology, the water pressure must reach 6L to produce the siphon, and if the water level is below 6L, the above situation may occur.

Solution: Turn the water button (which adjusts the water pressure) in the water tank up until it can siphon!

Answer, there should be none, otherwise it is easy to breed bacteria and insect pests.

The toilet is usually flushed with water into the tank after flushing the toilet.

Answer, there is no good quality here, otherwise.

It is easy to breed bacterial contamination.