在句首的only如果后面跟了副词、介词短语或从句等状语,则主句用倒装结构
如：Only in this way can you learn English well．
【注意】：only和所修饰的状语如果不在句首,则不倒装.
如：The boy was helped out only when his father arrived in a hurry．
【俊狼猎英】 欢迎追问