Once the C1 level is achieved, learners can use there ought to be to talk about desired states of affairs.
The rooms were dirty, there was no room service and there ought to be a lift since the rooms were on the 4th floor. (Cambridge English: Advanced; Swedish)
We came to the conclusion that there ought to be some changes to the club’s publicity. (Cambridge English: Advanced; Portuguese)
I think there ought to be more excursions and guided tours. (Cambridge English: Advanced; Swedish)
Learners at this level can also use ought to have + past participle to refer to desired states of affairs in the past.
Another point, which I think ought to have been better managed, was the boat trip on the Thames. (Cambridge English: Advanced; Polish)
However, the expert that I have consulted claims that this kind of polluted water is the most common consequence when placing gas stations and the government ought to have known that. (Cambridge English: Legal; Swedish)
We were taken by surprise when we didn’t get a tour guide. We ought to have booked one! (Cambridge English: Advanced; Greek)
C1 level learners use really with ought to to add emphasis.
Moreover, you really ought to ask for details about the timetable they’ve set for schooling hours, just to be sure that it fits with the way of studying you are accustomed to. (Cambridge English: Advanced; Greek)
This is what almost everyone thinks, but we really ought to think a little bit more about it. (Cambridge English: Advanced; Catalan)
One really ought to know the interests, wishes and demands of the receiver. (Cambridge English: Advanced; Slovak)
Learners can also use ought to in order to talk about something that is likely.
The fundamental function of accounting software is to record the numerous ordinary business activities, which may improve the efficiency of the company. Besides, it ought to provide useful information in decision-making. (Cambridge English: Financial; Chinese)
You ought not to be hungry. (Cambridge English: Advanced; Turkish)
The key difference between the C1 level and the C2 level is the use of the negative form. Although this is still a very low frequency item, C2 level learners use oughtn’t (without to) + verb and well as ought not to more frequently than at any other CEFR level.
They will most certainly have a banquet that day ... and you oughtn’t miss it for the world! (Cambridge English: Proficiency; Portuguese)
Secondly, there ought not to be a division between rich and poor. (Cambridge English: Proficiency; Dutch)
We ought not to forget that in the last twenty years the food industry has increased the number of chemicals used in its products. (Cambridge English: Proficiency; Spanish - Latin American)
Learners at this level can also use ought + subject + not to + verb to form (rhetorical) questions, often in formal contexts, but this is still done with very low frequency.
And if not, ought we not to learn from the mistakes of the past? (Cambridge English: Proficiency; Danish)
As a modal with a lower frequency, ought to is in many ways unlike its counterparts. There are, for example, few examples of questions, few examples of negatives and no examples of tag questions in learner work. Yet, it is widely used correctly. Ought teachers spend more time on this modal or should we focus attention on modals of higher frequency?