The air system was on; he would not need the filter sac.

No one could know that he had ever been in the air system.

They will insert the gas and the virus into large buildings through their air systems.

He knew only that the cage's air system had tried to kill him.

Told me to make certain no one put anything in the air system.

Have the air system put back into operation at once.

The tailored plants in the air system were alive and well.

Then I got to work on the air system.

It was not so very different from the purring of the air system she had heard all her life.

The outcome, he said, would depend on the quality of the air system.