Verified answer

Hi I'm a native Japanese guy.

It's complete sentence with S & V.

Of course you can add some modifiers, like "Tsukueno shita ni neko ga imasu (There is a cat under the table.)"

Yup. Learned that phrase while I was in Japan and used it a lot. Though I mostly used it to ask if a store had something. "Hashi ga arimasu ka?"