cer·tain·ly /-li/
  (ad.)一定,必定
  Cer·tain·ly, adv. Without doubt or question; unquestionably.
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  certainly
       adv : definitely or positively (`sure' is sometimes used
             informally for `surely'); "the results are surely
             encouraging"; "she certainly is a hard worker"; "it's
             going to be a good day for sure"; "they are coming, for
             certain"; "they thought he had been killed sure
             enough"; "he'll win sure as shooting"; "they sure smell
             good"; "sure he'll come" [syn: surely, sure, for
             sure, for certain, sure enough, sure as shooting]