52.2 The Aspect Particle 開 hoi1 (Habitual)

We can use the aspect particle 開 hoi1 to indicate that we do an action habitually. The aspect particle 開 hoi1 often adds the meaning of ‘usually’ to a sentence. In grammar, this aspect is called the habitual aspect.

In Grammar and Vocabulary 41.3, we learned the adverb of frequency 通常 tung1 soeng4 (‘usually’). 開 hoi1 and 通常 tung1 soeng4 add similar meaning to a sentence. We can often use them interchangeably.

Note that, however, there is a subtle difference between 開 hoi1 and 通常 tung1 soeng4. We usually use 開 hoi1 for habits that have developed over time, while we usually use 通常 tung1 soeng4 when we are simply indicating how frequently something is done.