Aftersomanydayswithoutrain,thegroundquickly________thelittlerainthatfelllastnight.
设二次型f(x1,x2)=x12+4x1x2+4x22经正交变换化为二次型，求ab的值。
Theenginehasbrokenandtheboatis______onthewater.
________(fail)severaltimes,theyneedsomeencouragement.
Theteamplayedhardbecausethechampionshipofthestatewas______.
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