Hi Ei Ei shwe zin The two sentences have almost the same meaning, but there is a slight difference in emphasis. The first sentence, "I've never realised before how hard the work is," uses the contraction "I've" to mean "I have." This implies that the speaker has recently come to the realisation that the work is hard, but it is not clear when exactly this realisation occurred. The use of the present perfect tense "have realised" suggests that this is a recent realisation, but it is not specified. The second sentence, "I never realised before how hard the work is," uses the simple past tense "realised" instead of the present perfect tense. This implies that the realisation occurred at a specific point in the past, but it is not clear when exactly that was. The use of the simple past tense suggests that this realisation is not recent, but rather happened at some point before the present moment. Hopes this helps :)