Sihai network

Why did his girlfriend die

A man and his girlfriend went for a walk by the river. Suddenly his girlfriend fell into the river. The man jumped into the water to look for his girlfriend, but he couldn't find his girlfriend. He left here sadly. After a few years, he revisited his hometown. At this time, he saw an old man fishing, but the fish caught by the old man had no water grass. He asked the old man why the fish was not stained with one The old man said, the river has never grown water plants. At this point, the man jumped into the water and committed suicide. Why?