Most commen solid is plastic.
~> The most common solid is plastic.

Beacause plastic is can find in everywhere!
~> Because plastic can be found everywhere!

In school, house,toilet,reastrang!
~> It can be found in schools, houses, toilets and restaurants!

And plastic is make a averything! Plastic is cup,plate,computer,table,toy and ellse.
~> Also, plastic is used to make a lot of things like cups, plates, computers, tables, toys and so on.