Explanation
Expresses that something doesn't always happen or there are occasions when it doesn't happen.
Formation
Verb-negative form + ことがある
Detailed explanation
The ないことがある grammar point is used to indicate that there are instances or times when something doesn't happen or isn't done. It is formed by combining the negative form of a verb (ない) with ことがある.
Examples
彼は会議に出席しないことがある。
Kare wa kaigi ni shusseki shinai koto ga aru.
There are times when he doesn't attend meetings.
この電車は定刻に来ないことがある。
Kono densha wa teikoku ni konai koto ga aru.
There are occasions when this train doesn't come on time.
私は朝食を食べないことがある。
Watashi wa choushoku o tabenai koto ga aru.
There are times when I don't eat breakfast.
彼女は電話に出ないことがある。
Kanojo wa denwa ni denai koto ga aru.
There are occasions when she doesn't answer the phone.
Practice
Grammar content sourced from hanabira.org.