OE

mitigate, forestall That “floodwaters had already breached the library’s walls” sounds very bad—the water is already inside. The signal word “but” tells you that the sentence is going to change direction, and indeed, the volunteers are “hopeful.” So you’re looking for something good in the blank—although it doesn’t seem like they’re going to cure the problem entirely. A good fill-in would be something like limit or hold back. Exacerbate (make more severe, aggravate), abase (reduce in prestige, humiliate), bolster (support, boost), and flummox (confuse) do not contain any pairs. ​​
_________________