French is.learnt.by children.
A box of sweets is bought by Mum.
A telephone is.used.by everyone.
Следующее предложение смысла не имеет, но всё же. Friends are lost by ex-friends. (Кстати, теряются без Ь)
The song was sung by the whole school.
Предположив, что это " обед", The lunch will be had by all the pupils./ The lunch will be eaten by all the pupils.