1.   But we know that three-generational households were in fact as rare in the past as they are today.

2.   However, end-stage renal failure caused by chronic hypokalemia is extremely rare in humans.

3.   Impeachment is quite rare in presidential systems.

4.   It is a manner of speech now increasingly rare in the world, faded and ever weakening like a lost radio signal.

5.   It was arguably one of those times, rare in recent years, that a California law helped bring change nationwide.

6.   Johnstone has confronted his fall from grace with the kind of honest self-awareness that is rare in habitual drinkers.

7.   She especially appreciated his willingness, so rare in the men she knew, to reveal and analyze his feelings.