Translation:The swan is eating the worms I am giving it.
What is interesting is that you don't need "that" in this sentence in Danish. Svanen spiser ormene jeg giver den rather than Svanen spiser ormene at jeg giver den, but omitting it from the correct English translation, while making some pedagogical sense, doesn't make any sense for our fluid understanding of both languages. I'm here stuck because 'The swan is eating the worms I am giving it.' is grammatically all over the place. The swan is eating the worms that I am giving it would be somewhat correct but alien to an English speaker. It's like a doubly continuous sentence.