Scotland’s education secretary has said it is “inconceivable” that all pupils will return to school at the same time.
John Swinney said there would have to be a “phased” return to allow for social distancing.
That could mean classes being split, with “some pupils using classrooms in the morning and others in the afternoon”.
Schools have been closed across Scotland since the coronavirus lockdown was introduced last month.
The Scottish government says there are early signs that the impact of the virus is being contained.
It has published a document outlining the basis of an exit strategy from the UK-wide lockdown.
Part of that process could involve pupils going back to school with limited class sizes.
Classrooms could also be redesigned to allow young people and teachers to work in a safe environment.
Mr Swinney said: “The idea that schools will be reconvening and all pupils will be back at the same time on the same day is not a circumstance I can envisage any time soon.
“There is clearly disruption to the learning of young people right now and we need to find the most effective way to bring school communities back together again and to make sure that formal learning can be revived.
“What we have to look at is how we might bring schools back on a phased basis with different groups of pupils coming back at different times, or changes to the school day to accommodate different groupings of individual pupils.”
Last week, First Minister Nicola Sturgeon accepted it would be difficult to implement social distancing in schools – especially where younger children were involved.
Mr Swinney said there was still no public health case for schools reopening – but when they do, it will be under very different circumstances.
He said: “If people were wondering, would we be in a position any time soon to bring back entire school communities on the basis that they were working before Covid, I think that’s inconceivable.
“In some circumstances you would have secondary schools with 1,600 of 1,700 people coming back on the same day into buildings which are always congested with children, young people and teachers.
“What we must undertake is a proper analysis of how can operate formal education while respecting social distancing and the other issues that are important in the public health advice.”
Health and wellbeing
Scotland’s largest teachers’ union, the EIS, also backs a “blended” approach to education when schools eventually reopen.
The union’s general secretary Larry Flanagan said: “We have been clear that until the Scottish government has the capacity to test, track and isolate the virus, it would be impossible for teachers to return to work and be confident that they are in a safe environment.
“Beyond that, there is a lot of discussion about how schools will be able to operate with social distancing in place.
“I think we are looking at some kind of blended approach whereby there is some continuation of working outside of the school and getting some back in.
He added: “Our instinct is that we need to offer all pupils some access to school education because the interaction with their fellow pupils and teachers is integral to their health and wellbeing.
“We need to have universal provision but that clearly won’t be under the normal arrangement that people are used to.”