Adverb of Frequency

Kita mengenal adverb of frequency misalnya: Always, often, frequently, sometimes, never, ever, occasionally, eventually, once a week, once a year, hardly, seldom, rarely, barely.
Tapi kita harus hati-hati terhadap penggunaan adverb of frequently karena ketika mereka digunakan kedalam tenses yang berbeda akan menghasilkan makna yang berbeda.
1. Simple present + Adverb of frequency → Present habitual action
    ex. He always helps me
2. Simple past + Adverb of frequency → Past habitual action (kebiasaan di masa lalu)
    ex. he always helped me last year
3. Simple future + Adverb of frequency → Future habitual action
    ex. He always help  me next year
4. Perfect/perfect continuous + Adverb of frequency (time duration process) → Process action
    ex. He have always helped me now
          He has always been helping me now
5. Present continuous + Adverb of frequency → Annoying habitual (kebiasaan yang menjengkelkan)
    ex. He is always knocking at my door