區別是：
Not at all指的是一點也不，根本不。
certainly not指的是不，當然不行;決不。
例句辨析：
Not at all
1、I am not an obsessive. Not at all.
我不是個強迫症患者，完全不是。
2、It"s not at all certain whether I"ll come tomorrow.
我明天還不定來不來呢。
3、I"m not at all secretive, and I"m pretty good at calling a spade a spade.
我不會遮遮掩掩，我喜歡直言不諱。
certainly not
1、He"s very attractive, though certainly not a ladykiller.
他很有魅力，雖然還不至於使女人一見傾心。
2、I don"t know just exactly how old his child is, but certainly not older than twenty.
他的孩子究竟多大我不清楚，反正不超過20歲。
3、She might be a little common at times, but she was certainly not boring.
她有時候可能有點粗俗，但絕對不會讓人生厭。
區別是：
Not at all指的是一點也不，根本不。
certainly not指的是不，當然不行;決不。
例句辨析：
Not at all
1、I am not an obsessive. Not at all.
我不是個強迫症患者，完全不是。
2、It"s not at all certain whether I"ll come tomorrow.
我明天還不定來不來呢。
3、I"m not at all secretive, and I"m pretty good at calling a spade a spade.
我不會遮遮掩掩，我喜歡直言不諱。
certainly not
1、He"s very attractive, though certainly not a ladykiller.
他很有魅力，雖然還不至於使女人一見傾心。
2、I don"t know just exactly how old his child is, but certainly not older than twenty.
他的孩子究竟多大我不清楚，反正不超過20歲。
3、She might be a little common at times, but she was certainly not boring.
她有時候可能有點粗俗，但絕對不會讓人生厭。