つぐ 和 さす 和 そそぐ 的差別在哪裡？如果不好說明，請提供一些例句。

When you pour drink into a cup or a glass, “のみものを つぐ”
Only drink

When you boil some noodles and the hot water almost overflow, you can pour some cold water to stop the overflow, “みずを さす”
The image of さす is subtract.
せっかく上手くいってるのに、水を差すなよ
In spite of things doing well, when somebody does / says disturbing unintentionally, you can say ”水を差す”

When you pour hot water into the bathtub, “ゆを そそぐ”
The image of そそぐ is addition.
火に油を注ぐ
When you want to put out the fire, if you pour oil into the fire, so the fire will spread more.