Объясните, зачем нужны предметные и покровные стёкла?

Rex tells Tiny about the brown house.But he misses some words.Help Tiny to fill in the words.

1)There ____ bedrooms in the house

2)There ___ doors in the hall

3)There ____ no windows in the hall

4)There ___ a kitchen in the house

5)There ____a living room in the house

6)There ____a pantry in the house

7) There___a lot of windows in the house

какие слова нужно вставить ?