They both watch in amazement as a second alien appears and begins communicating with the first.

The aliens have already begun their attack on Earth.

There was nothing now that could stop what the aliens had begun.

"These aliens on this planet," she began with no preamble.

As he started toward them, the aliens began to wave their leaves/ hands/protuberances.

The aliens began to mutter and shift about, talking among themselves.

Between 17:00 and 18:00 hours the aliens began to stir.

Everyone goes down to the basement, the only safe room available, as the aliens begin forcing the kitchen door open.

Many feared that if truly angered, the aliens might begin to end lives.

The alien had not practiced his profession for several years, and began to wonder whether he was losing the touch.