一道SAT语法题
37.FabricwasveryexpensiveintheUnitedStatesbeforetheundustrialrevolution,thisiswhyscrapsweresavedandrecycledintosuchitemsaspatchworkquiltsanddollclothes.
A.revolution,thisiswhy
B.revolution,thisexplainswhy
C.revolution,andso
D.revolutionandsothat
E.revolution;resultingin
为什么选C?and和so不都是连词吗?连词不是不可以连用吗?