No later than與Not later than意思並沒有分別,而且也是地道的英文
Cambridge Dictionary Online,在later條下,就這樣說
later adverb /ˈleɪ.tər //-t ̬ɚ/ adv at a time in the future or after the time you have mentioned He'll be back later.We could always go later in the season.Police questioned him and he was later arrested.
later on at a time in the future, or after the time you have mentioned What are you doing later on this evening?Shall I go and fetch her later on?Later on, we could go and have a meal if you like.
no/not later than not after She said she'd prefer us to arrive no later than nine o'clock.(Definition of later adverb from the Cambridge Advanced Learner's Dictionary)
只不過no later than常用點
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2010-11-10 11:07:04 補充:
http://www.ldoceonline.com/dictionary/later_1
3.not later than somethingused to say that something must be done by a particular time in the future: Completed entry forms should arrive not later than 31st July.