a.

1. （钟、表等）发条走完的；（电池）耗尽的
   Standing on the table was a run-down clock.

   桌子上放着一只走停了的钟。

2. 精疲力竭的；衰弱的
   We're completely run-down and need a thorough rest.

   我们精疲力尽了，需要彻底休息。

3. 失修的；破败的；衰败的
   I bought a run-down farm house and plan to fix it up.

   我买了一间破败的农舍，打算整修整修。

   We will plan to rehabilitate the run-down neighborhood.

   我们计划重建这个破落的街区。