Dharana is intermittent because it's disturbed when the disturbance goes away then it is dharana. The disturbance may come but it will be very little and it will mind flow like they say oil being poured from one vessel to another so like continuous flow not discrete but continuous flow that leads to absorption if you can hold on to that dharana, he says. haa patthya haa withdrawal and sixth  is also effort dharana is effort darana is effort and samadhi also it will be achieved but it will just before that there will be a certain kind of effort very subtle focus is necessary to deepen dharana into samadhi meditation into sam