Keys shaped like credit cards as if one walks around with unassigned slots in one's wallet.

卡式的钥匙 好像谁的钱包都有空的卡槽似的。

With unassigned slots in one's wallet.

都有空的卡槽似的。

Now that the only unassigned wall color is yellow, this must be applied to the first house, where clue seven says the Dunhill smoker lives.

黄色，那就肯定是第一栋房子了，线索七说抽登喜路雪茄的人就住在这里。

If fewer people are coming in on any one day, at least they don't need as much space: they can find unassigned desks and the firm can save some money.

如果每天来办公室的人越来越少，那么他们就不需要那么大的空间：他们不必有固定的工位，公司就可以节省一笔钱。