Plans are being made for how schools in England will start to reopen next month.
However, there is disagreement over whether children will be returning too soon and how schools can be made safe.
When will schools reopen?
In England, ministers say schools should prepare to begin to open for more pupils from 1 June.
This would be for those in nursery and pre-school, Reception and Years 1 and 6 at primary school. At secondary school and college, Years 10 and 12 would return first.
Only a tiny fraction of the regular school population are likely to attend.
Is it safe to reopen schools?
Young children are superspreaders of other diseases, such as flu, but so far appear to be at low risk of becoming very ill from coronavirus.
However, nine education and teachers' unions have expressed concern about schools reopening next month - saying it was still too early to be safe.
The unions called for a delay until a full testing regime was in place and said that "classrooms of four and five-year olds could become sources of Covid-19 transmission and spread".
The government does not recommend face coverings in schools, except in a few cases, even if teachers cannot maintain social distancing.
How will schools reopen?
It says they should:
Reduce class sizes and keep children in small groups without mixing with others
Stagger break and lunch times, and school arrival and departure times
Clean more frequently, and reduce the use of shared items and outdoor space
Scotland's largest teachers' union the EIS says the country will need to adopt "a new blended approach" to teaching and learning.
This could include a combination of part-time learning at school and home or online working.
The Welsh government has set out five key principles which would enable schools to reopen. These include having guidance to support social distancing, managing attendance and wider protective actions.
In Northern Ireland, the education minister said "practical measures" like PPE for staff, social distancing at mealtimes and safety for school transport needed to be arranged.
Do I have to send my children to school?
At present, it is not compulsory for key worker parents to send their children to school, and there are no fines for those who have not taken up the places available to them.
It is expected that this temporary arrangement - where usual sanctions do not apply - will continue for all parents of any year groups going back in England during the summer term.
What about disadvantaged children?
Approximately 2% of pupils - those considered vulnerable and the children of critical workers - are attending school in person.
The government is urging teachers and local authorities to encourage more youngsters from these backgrounds to go to classes each day.
Concerns have been raised about the harm to disadvantaged children of missing school, and Education Select Committee chairman Robert Halfon wants retired teachers among others to help them catch up.
What's happening in other countries?
How are children currently being educated at home?
Schools have tried to continue a limited curriculum online, relying on parents and guardians to supervise.
Educationalists say that parents should not be expected to do the teacher's job, but they can try to maintain a routine of learning and study habits - even if it's only for an hour or two a day.