Questions & Answers about Støvet ligger på gulvet.
Why does støvet end with -et, and why isn't there a separate word for "the"?
In Norwegian, the definite article is usually attached to the noun as a suffix. Støv (dust) is a neuter noun, so you add -et to form the definite singular: støvet means "the dust." There's no separate word like the.
What does ligger mean, and why is it used here instead of er?
Ligger is the present tense of ligge (to lie). In Norwegian, to describe where something is situated on a surface, you often use ligge (similar to English "to lie"). So Støvet ligger på gulvet literally means "The dust lies on the floor." You can say Støvet er på gulvet ("The dust is on the floor") and it'll be understood, but ligger is more idiomatic for location.
What form and tense is ligger, and what are the other forms of ligge?
Ligger is the present tense. The infinitive is ligge, the simple past is lå, and the past participle is ligget.
Why is it på gulvet, not i gulvet?
The preposition på means "on" or "at" when talking about surfaces. Gulvet is "the floor." So på gulvet means "on the floor." I gulvet would mean "inside the floor," which doesn't make sense here.