The upward rush of the machine slackened off; a moment later they were hanging motionless in the air.

飞机上升的冲刺减缓下来，不一会儿他们便一动不动是在了空中。

We slacken off the circulation when they're right way up, so that they're half starved, and double the flow of surrogate when they're upside down.

他们直立时我们便减缓转速，让他们感到很饥饿；他们倒立时我们就加倍供应代血剂。