undoubtedly词根

词根是doubt，怀疑的意思。doubt-doubted受到怀疑的-doubtedly有怀疑地-undoubtedly毫无疑问。如，Undoubtedly，the pollution problem in this area is becoming increasingly serious.在英语中，很多动词都有这种变化，如expect期待-expected想要的，期待的-expectedly期待地-unexpectedly出乎意料地。