Преобразуйте существительные во множественное число и произведите все необходимые изменения.
The sheep is eating grass.
Her brother in law is an engineer.
The roof of this house is flat.
This is the plan of this report.
There is a yellow leaf on the ground.
This is a black tie.
Преобразуйте существительные в единственное число и произведите все необходимые изменения.
The wolves are stronger than the foxes.
The leaves are on the trees.
The oxen are in the yards.
The beautiful flowers are in the gardens.
There are some people in the classrooms.
The cases are in the lost-property offices.

 подскажите какой класс? 

The sheep are eating grass. Their brothers in law are engineers. The roofs of these houses are flat. These are the plans of these reports. There are yellow leaves on the ground. Thiese are black ties.The wolf is stronger than the fox. The leaf is on the tree. The ox is in the yard. The beautiful flower is in the garden. There is a man in the classroom. The case is in the lost-property office.