Time and again the aliens had attacked, but in comparatively insignificant numbers.

The other three aliens attacked simultaneously; it was over in a second.

No one had any idea why the aliens had attacked.

At least, nothing that would explain why the aliens attacked the colony.

"Why would the aliens purposefully not attack one colony world?"

"We think the aliens will attack and, depending on how the conflict goes, might join forces with the Sheen."

This does not exclude cases where the aliens attack us.

"If the aliens attack us again, we won't have a chance."

While he is on board, aliens attack his mothership and destroy it.

The aliens had attacked, although she did not know why.