Now let's fast-forward to the 1990s when those two teams of astronomers I mentioned at the outset were inspired by this reasoning to measure the rate at which the expansion has been slowing.
现在让我们快进到二十世纪90年代， 我开始提到的 那两个天文学家小组 受到这个推理的启发 来测量 这种扩张放缓的速率。