The phrase "aliens building" is correct and usable in written English.
It can be used in contexts discussing extraterrestrial beings engaged in construction or creation activities.
Example: "The documentary explored the theory of aliens building ancient structures on Earth."
Alternatives: "extraterrestrials constructing" or "foreign beings creating".
America will create a huge decrease in the number of illegal aliens by building this wall and keeping Mexicans in Mexico, and there will be a big jump in American employment.
He warns the group that the aliens are building a transmitter (beneath the Costco store) which will summon their armada to destroy the earth, and is expelled from the watch for his deception.
"I would refer you instantly to Claus's Desert Island Discs, probably the best I ever heard, telling us about his early life in Berlin as a small boy going to great concerts by the likes of Furtwängler and Klemperer, then coming here as an enemy alien and building a career at the very heart of British public life.
Indeed, the buzz is reminiscent of extensive news coverage that surrounded KIC 8462852, now known as Tabby's Star, last year when it was suggested by Penn State astronomer Jason Wright that the star's odd dimming behavior might be the result of an alien civilization building a mega-structure blocking the star's light.
But no Planet X researcher was more beleaguered than Percival Lowell, who launched into the search for the distant object in an attempt to redeem himself after he became a laughing stock for suggesting that aliens might be building canals on Mars.
There may yet be intelligent aliens out there, building vast trans-planetary empires to collect and utilize as much energy as possible, but the evidence for them is nil thus far.
Firaxis' 2012 strategy title was a remake of a 1994 original, UFO: Enemy Unknown, which cast you as the commander charged with responding to an alien invasion of Earth – building up the eponymous organisation, responding to attacks across the globe, and hunting down alien operating bases.
He relishes this somewhat alien approach to team building.
